Tag: hydroponic

The alternative hypotheses we present in figure 2 could be addressed with herbarium specimens for plant species with long-term herbarium records and which vary in their phenological sensitivities to climate change. While collections may not always allow us to differentiate between alternative scenarios, they could reveal how herbivory changes with warming for plants across a range of phenological sensitivities, and inform field experiments to tease apart mechanisms. In some cases, it may be possible to test for herbivory by novel herbivores by quantifying types of damage that can be traced back to particular insect genera or species, such as galls and leaf mines , or chewing damage that is characteristic of certain insect orders, e.g. margin feeding, circular hole feeding, and skeletonization. Butterfly collections might also help in resolving alternative scenarios, although we suspect that larvae, responsible for most herbivore damage, may be under-represented in collections compared to adult Lepidoptera, and flight phenology may not be correlated with larval phenology . The mismatch between adult and larval butterfly life histories is a challenge for using butterfly collections to explore phenological asynchronies. However, there are also scenarios in which phenological change at the adult stage may affect herbivory, which may offer opportunities to use the extensive collections of butterflies and moths that are available. For example, some Lepidoptera species may develop ‘lost generations’, raspberry container growing in which warmer temperatures signal caterpillars to develop into adults rather than entering diapause. The adults of the last generation may suffer high mortality rates at the onset of winter; for a more thorough discussion of this topic, see.

Museum specimens of moths and butterflies could inform how common it is for Lepidoptera species to add another generation in response to climate change, and contrasting herbarium specimens of their host plants could reveal how herbivory is differentially impacted by species that have and have not added generations with climate change.One of the most supported predictions in global change biology is that species’ ranges will shift poleward and upward in elevation as the climate warms. For many insect species, poleward range expansion may be explained by increased over-winter survival and/or feeding owing to warmer winters. For multivoltine insects, longer growing seasons can also increase the number of generations completed per year, leading to population growth that might facilitate range expansion if host plants are available. Most predictions on plant species’ range shifts are predicated on the assumption that abiotic factors determine range edges; however, biotic factors can also contribute to range limits. There is also growing evidence that biotic factors, such as herbivores and disease can interact with abiotic factors to determine the trailing range edges of some plant species. However, the factors that drive range limits at leading and trailing edges remain unknown for most species. Biological collections typically have associated metadata describing when and where collections were made, and therefore provide rich data on species distributions and distributional shifts over time. Species distribution models are commonly used to map past and present distributions, but they are intrinsically limited by the number and representation of input records, and, in the case of global change research, the number of records available from before and after global change.

The extensive digitization efforts currently underway for insect and plant specimens will improve our predictions and ability to track changing distributions. For well sampled plant species, we might also be able to investigate changes in herbivory at poleward range edges to determine if it has declined over time as plant ranges expand into novel habitats—an extension of the enemy release hypothesis associated with species invasions, discussed below. Larger digital collections of insect herbivores will provide the opportunity to compare range shifts across insect clades and to identify traits that govern range expansion and contraction. For example, we might expect that warmer winters will disrupt winter diapause for many insect species, leading to range contraction and decline, while those that do not have diapause will benefit from higher rates of winter survival. However, it is also possible that insects with diapause are more likely to maintain phenological synchrony with on how herbivore damage will change over time. Species traits might also determine whether species shift over time or space, and how these two responses trade-off . The ability of insect herbivores to switch host plants may be another factor that constrains or facilitates herbivore range expansion, and thus plant –herbivore interaction strengths. Specialized insects that do not feed on newly encountered plant species may be limited in their geographical spread, whereas more generalist herbivores would be less constrained. Herbaria may capture such switches to novel hosts, showing up as new types of herbivore damage on specimens as host plants and their insect herbivores shift their distributions and provide the opportunity for novel plant –herbivore interactions. For example, leaf mines and galls—which are preserved on herbarium specimens—are made by a wide variety of insect herbivore taxa, including some of the most diverse groups of insects—Lepidoptera, Coleoptera , and Diptera —and are often specific to insect genera or species .

The Lepidoptera that make leaf mines are not well represented in long-term citizen science data because leaf miners are typically micromoths, which are not the focus of long-term observations, and leaf mining and galling damage are only rarely included in herbivory studies, which tend to focus on chewing damage. Thus, herbarium specimens provide a record of a unique insect herbivore fauna not represented in long-term herbivore monitoring or herbivory studies. Herbarium specimens may also provide data on a key hypothesis in global change biology that is based on theory which dates back to Darwin: the role of natural enemy release in species invasions. The enemy release hypothesis describes the escape from native predators and parasites when species are introduced into novel habitats. While there is evidence that introduced plants escape their native herbivores, it is unclear how long this ‘release’ persists. Herbarium specimens can provide rare long-term data on herbivory and disease pressure that allows us to resolve this question. In a well-documented example, Schilthuizen et al. used herbarium specimens to show that the non-native cherry tree, Prunus serotina, acquired higher rates of herbivory over time after its introduction to Europe, while its native congener, Prunus padus, had stable herbivory levels over the same time period. This led to field investigations into the contemporary herbivore communities for these congeners, which revealed that, surprisingly, P. serotina had a richer herbivore community than the native P. padus, and that P. serotina had acquired specialized herbivores from other native host genera. This supports the hypothesis that non-native plants accumulate herbivore taxa over time in their novel habitats, which might have significant implications for plants that shift in their geographical distributions.Urbanization affects insect herbivores via a variety of mechanisms, including habitat fragmentation, habitat and host plant loss, and introduction of novel host plants that attract and support non-native herbivore communities. Given these concurrent pressures, the effects of urbanization on plant – herbivore relationships are complex and varied . However, in recent years, it has become increasingly clear that a key aspect of urbanization, the urban heat island effect, can drive relationships between plants and herbivores and may uniquely inform climate change predictions. The urban heat-island effect—the local warming of urban areas relative to surrounding countryside—increases urban temperatures 1– 128C higher than rural temperatures. Thus, local warming caused by urban development is similar in magnitude to warming expected globally over the next 100þ years, and it has therefore been suggested that cities may provide insights into the future effects of climate change. Like global warming, urban warming drives phenological advance in plants and insect herbivores. For example, plants leaf out and flower earlier in cities than in nearby rural areas, and urban heat is associated with earlier egg production for certain insect herbivore species. While the effects of warming global temperatures on the synchrony of plant –herbivore interactions is still generally unresolved owing to a lack of data, these relationships can be studied across urban temperature gradients, blueberry plant pot and there is some evidence for reduced synchrony between insect herbivores and their natural enemies as a result of urban warming. Because of the parallels between the abiotic and biotic effects of urban and global warming, natural history collections from urban areas may allow us to more broadly predict how global climate warming will affect interactions between plants and their insect herbivores. Phenology data from specimens—e.g. flowering, leaf-out, insect flight— paired with data on urbanization intensity in the areas where specimens were collected could inform predictionson phenological change and synchrony for a broad range of plant and herbivore species. Specimen data from urban areas are, perhaps surprisingly, plentiful. A recent study shows that across three areas with large digitized herbarium collections—the US, South Africa and Australia—plant specimens are often collected close to natural history museums or roads. Thus, specimens could be used to explore urban natural gradients.

Like temperature, urbanization can be easily assigned to historical specimens via contemporary measurements or existing data. As a proxy for urbanization, we can use human population density data from censuses, which many countries have been collecting since the early 1900s, and in some places urbanization can be translated from historical maps or as impervious surface derived from satellite imagery. One novel approach might be to derive markers of urbanization from the herbarium specimens themselves, for example, signature pollutants, although disentangling the contributions of different drivers would then present additional challenges. In recent years, growing evidence shows that urban warming may increase abundance of certain herbivores, notably sapfeeders, potentially leading to more insect damage on urban than on rural plants, a pattern that has been documented by entomologists for over a century. Sapfeeding herbivores, such as scale insects and aphids, are often preserved on leaves and branches and thus may provide insights into changing herbivore pressure in response to urbanization. In a recent study, Youngsteadt et al. counted armoured scale insects on branches of herbarium specimens of red maple Acer rubrum and on branches of live trees across an urban warming gradient. Using these data, they showed that interannual warming and urban warming may have surprisingly congruent effects on scale insect prevalence. In box 2, we discuss how herbarium specimens might be used to investigate more complicated interactions between multiple trophic levels, relationships that could inform biological control efforts and management of urban plants. While the urban heat island effect benefits certain herbivores that survive within the urban matrix by advancing their phenolog and increasing their abundance, urbanization also excludes some insect species—a pattern which has been documented with insect museum specimens—making the effects of urbanization on herbivore damage to plants difficult to predict. Long-term records of butterfly flight from Britain showed that habitat loss is associated with butterfly decline, especially for species that are less mobile and are habitat specialists. Relatedly, a recent study across 16 European cities showed that leaf chewing damage was lower in cities relative to nearby rural areas, perhaps driven in part by higher rates of bird and ant predation on insect herbivores in cities than in rural areas. Thus, a pattern that might be emerging from the literature is that certain sap-feeding insects benefit from urban heat , while leaf chewing and the insects that cause this type of damage, notably Lepidoptera, decline in response to loss of habitat and host plants caused by urbanization. This finding suggests that the effects of bottom-up versus top-down forces driving insect herbivore fitness might differ among feeding guilds . Measurements of broad-scale chewing herbivory , presence of sap-feeders, and incidence of sooty mould as a proxy from herbarium specimens, along with insect herbivore occurrence data, could be used to test this hypothesis . In addition to describing the effects of urbanization at the local scale, museum specimens may also reveal how urbanization affects species distributions at broader spatial scales. For example, while urbanization may disrupt poleward range expansion for some species, it is possible that cities serve as warm habitat stepping stones for species with long-distance dispersal mechanisms, facilitating their poleward expansion. The insects that create leaf mines have been described as ‘aerial plankton’ because they tend to disperse long distances. Herbarium specimens might capture this rapid northern expansion of leaf mining insects and provide a record of shifting interactions with native plants that may be more likely to respond in time than space —see box 1.

A study in natural ecosystems comparing forest and savanna found species richness to be affected by habitat and strata ; the two environments clearly differentiated in terms of their species composition . In our study, canopy vegetation was not a strong driver for the community of twig-nesting ants since our best models did not include a VCI. However, species compositional differences observed across both vegetation layers could be an effect of microhabitat diversity and canopy connectivity . Providing complex vegetation not only promotes ant diversity but also other organisms that facilitate ant colonization into new twigs. Presumably ants often nest in hollow branches of trees that have been previously dwelled or inhabited by beetles . Moreover diversity of trees might also provide nesting resources that are different in terms of how difficult or attractive they are to dig cavities, for example studies have found that tropical woods can be different in terms of their structure, chemistry and biology ; this could suggest important drivers in the differentiation of ants that inhabit them. We found a large number of arboreal twig-nesting ant species in this coffee agroecosystem study supporting the notion that managed ecosystems, such as agroforestry systems in the tropics, blueberries in containers have the potential to host a great diversity of species. A number of previous studies have provided evidence that ant diversity increases control of pests and fungal diseases . We document here that increases in nest entrance size diversity on an individual tree relates to increases in ant diversity on trees. This may thus have important implications for promoting ants as biological control agents in agroforestry systems.

We conclude that the availability of a variety of nesting options and vegetation strata are important drivers of species diversity and support the idea that niche partitioning drives species coexistence . Future studies should further investigate the competitive hierarchies of the species colonizing twigs if we want to understand how species using similar resources interact with each other; and evaluate colony fitness in face of multiple resource use, as has been done in the past for colonies of Cephalotes persimilis . Since ants often engage in interactions that deliver ecosystem services future studies should focus on evaluating roles of different ant combinations using a diverse array of twig entrance sizes in agricultural pest control. Furthermore, we have learned from this study that the structuring of ant communities is multi-factorial and that local as well as regional factors should be considered when explaining species assemblages in the tropics. Habitat complexity is critical for the functioning of ecological communities in both terrestrial and aquatic systems. Processes such as resource foraging, colonization, and species interactions often depend on the level of heterogeneity in the configuration of physical elements in a habitat . Vegetation connectivity and structure are important components of habitat complexity and can influence species interactions and community patterns at local scales. In aquatic systems, more complex habitats made up of macrophytes support communities that are more diverse and abundant, and allow for greater food capture than systems without vegetation . In terrestrial systems, vegetation structure– such as the biomass of foliage and the variety of plant architectures– generally influences species composition, and increases species richness and abundance of numerous taxa . Additionally, vegetation structure can influence mobility and foraging success of vertebrates and invertebrates . In tropical ecosystems, ants are among the most abundant and bio-diverse of taxonomic groups , and are considered important predators, herbivores, and seed dispersers .

Ants are cursorial central-place foragers – organisms that forage from a central place to which they return with food to feed with the colony . Therefore, foraging and discovery of food resources is strongly constrained by the need to construct and follow trails along vegetation . This is particularly relevant for ants using the arboreal stratum as their primary foraging space . For instance, the availability of vegetation connections can maximize ants’ foraging efficiency, locomotion, and velocity , as well as contribute to changes in community composition and species richness . The availability of such resources can ultimately lead to differences in resource utilization by ant communities . In tropical agricultural systems, especially agroforests, ants play important ecological roles , and management practices can strongly influence ant behavior and their potential for providing biological pest control services . Indeed, one of the oldest known records of the use of ants for pest control dates to 304 A.D in citrus plantations in China. In these systems artificial connections made of bamboo were used by farmers to facilitate foraging by the Weaver Ant to suppress damaging phytophagous insects . In that same study, Huang and Yan report anecdotal evidence that suggests equal yields in orchards that use chemicals vs. orchards that use ant bridges to control for pests. Similarly, Peng et al. , report lower levels of fruit damage in cashew with the presence of weaver ants. However, as vegetation complexity declines in agroecosystems, tree density and diversity may also decrease , as well as the possibility to generate connections between the arboreal vegetation, which might impact arthropod populations . The lack of connectivity between trees in managed systems can have a significant impact on the mobility of worker ants and their ability to control resources. This impact may be particularly marked at greater distances from the nest, where ant dominance may be lower . This in turn may influence the ecosystem services provided by ants, particularly the suppression of pest outbreaks .

Shaded coffee plantations, which maintain high levels of shade and structural complexity can sustain complex networks of organisms, which can result in biological pest control . In coffee systems, ants are a functionally diverse and abundant group of ground and arboreal-nesting arthropods and are considered important biological control agents . Ants are predators of the most devastating coffee pest, the coffee berry borer , a beetle that drills cavities in coffee berries and severely damages the seed . Several species of arboreal ants, with nests attached to or inside tree trunks, branches, or twigs, control adult and immature stages of this pest either through direct predation or deterrence . Ants of the genus Azteca are numerically dominant in shaded coffee plantations. These ants forage intensively on coffee plants , and deter CBB adults by removing them from the coffee plant, therefore lowering fruit damage . In shaded coffee plantations, Azteca sericeasur ants nest on shade trees and access adjacent coffee plants through the leaf litter or available pathways, such as fallen branches, vines, and other vegetation , matching the description by Longino for this species in forest habitats. In more intensively managed coffee systems, with fewer and more distant nesting trees, connectivity may be sparse or absent and artificial connections might buffer against this loss. Vegetation structure and arboreal characteristics in coffee plantations are likely to be important factors influencing ant foraging behavior and nesting in arboreal ants . However, the influence of vegetation connectivity on the foraging of this dominant arboreal ant, and its effect on pest removal in coffee plantations has not yet been studied. Previous work has documented the importance of arboreal connections for ants and biological control in agricultural systems. For example, various studies and farmers’ manuals suggest that connecting nests to adjacent trees using bamboo strips enables weaver ants to colonize new trees, which increases ants’ efficiency in removing pests, including the pentatomid insect Tesserarotoma papillosa . However, there is little evidence about the effect of increasing arboreal connectivity on biological control using experimental data. We report an experiment testing the influence of adding connections between shade trees and coffee plants and its effects on CBB removal on coffee plants. To our knowledge, planting blueberries in pots this is the first study providing experimental data on the effect of adding connectivity on ant activity and pest removal in coffee agroecosystems. Specifically, we tested one hypothesis: connectivity affects CBB removal in this system by increasing recruitment rates of A. sericeasur ants to prey items; we predicted that 1) A. sericeasur ants use artificial connections between nesting trees and coffee plants; 2) plants with connectivity have higher ant activity than isolated plants; 3) plants with connections have grater removal rates of CBB by A. sericeasur ants; and 4) A. sericeasur activity and CBB removal rates by A. sericeasur ants decrease with increased distance from A. sericeasur nests. Within the farm, we haphazardly selected 20 non-overlapping sites located at least 10 m away from each other with one Inga micheliana tree containing an A. sericeasur carton nest on the tree trunk .

A. sericeasur is a polydomous, arboreal ant species , which occurs in ~13% of trees at our study site , and forages on coffee plants . Trees were selected only if ant nests were noticeably active. In each site, we quantified ant activity on the nest tree as the number of ants crossing a single point on the main trunk during one minute. This methodology has been used in previous studies to measure overall ant activity of a nest . We then selected the six coffee plants nearest to the nesting tree, making sure they were not directly touching each other or the tree by removing branches and vines . We then randomly assigned three of the coffee plants at each site to aconnection treatment and three as controls without connections, then measured ant activity on the plants by counting the number of ants passing a point on the central trunk for one minute. We connected treatment coffee plants to the nesting tree using jute string . Strings remained in the field for three days to allow for ant acclimation to disturbance and for ants to establish new foraging pathways. After three days, we returned to the sites and remeasured ant activity on the nesting tree and coffee plants. Observations took place between 10 am and 1 pm, and were immediately stopped as soon as it started raining, as this drastically decreases ant activity.To test how connectivity impacts potential biological control provided by ants, we added dead adult CBB onto connected and control coffee plants to directly assess ant removal rates. We collected CBB infested coffee berries from the field, dissected them, extracted female adult CBB individuals , and placed them in the freezer for up to 24 h, after which beetles were dead. Three days after placing strings and after reassessing ant activity, we placed 10 dead CBB adults on a small piece of white card on each coffee plant near the center of the trunk, left cards for 30 min, and then counted the number of CBB remaining. Restricting movement of sentinel prey, either by gluing them to observation sites or freezing them is a common technique for assessing predator behavior . We used frozen sentinel prey to increase the availability and similarity of beetles on cards and to reduce the potential for live prey to escape from the arena. To assess whether CBB removal was due to ant activity, we monitored cards across the plot over a period of 30 minutes and recorded any arthropods present. Only ants were observed on the cards, indicating that these were responsible for removing the CBB. Although we acknowledge that the use of dead prey may alter ant behavior, it is already well established that A. sericeasur both antagonizes and predates live CBB in the field, and reduces CBB infestation on plants . We used dead prey in this experiment to more readily assess ant removal rates and infer that these changes translate to changes in the bio-control efficiency of this ant on live prey. Immediately following each experiment, we characterized the vegetation in each site because several different environmental factors are known to influence ant foraging in coffee systems . We measured the percentage of canopy cover , coffee plant height, and distance from each coffee plant to the central Inga nest-tree.To test for statistical differences in ant activity on coffee plants before and after establishing connections we used a GLMM. We included time , treatment , coffee plant distance to nest tree, the interaction between time and treatment, and the interaction between time and distance as fixed effects . We also included coffee plant height and ant activity on nest tree as covariates.

While C0 wines in this study demonstrated lower alcohol content than shaded wines, previous literature corroborates cluster temperature reduction by partial solar radiation exclusion as an effective method to lessen sugar content in the grape berry and thus reduce alcohol content of wines . The effect of partial solar radiation exclusion in semi-arid climates on berry pH and TA is mixed. Previous work demonstrates partial solar radiation exclusion to reduce pH and increase TA in grape berries by reducing the thermal degradation of organic acids . However, in the present study, berry pH and TA at harvest were unaffected in either year by shade films . Nonetheless, there were apparent effects on wine pH and TA that were vintage dependent. In the present study, D3 wines had the lowest pH and highest TA, while C0 wines did not differ from the shade films D1, D4 or D5 in pH or TA in 2020. Differences observed in pH between the wines ultimately affect the colorimetric properties of these wines. In 2021, D4 and D5 wines showed the highest pH values. It is understood that the pH of the wines can shift the anthocyanin equilibrium in wine solution between the flavylium and quinoidal base forms . In the present study, D4 wines had the highest pH and the highest CI. In many cases, when pH rises, CI will decline as anthocyanin equilibrium shifts away from the flavylium form towards the colorless quinoidal forms . However, large plastic pots this was not the case in the present study. Rather, improved color intensity at elevated wine pH could be attributed to co-pigmentation in the wine matrix.

Co-pigmentation refers to non-covalent interactions between anthocyanins and cofactors such as flavonols, flavan-3-ols and proanthocyaninidins, that results in greater absorbance of the wine than color what would be indicated by anthocyanin content and pH conditions . Copigmentation in young wines was shown to increase color intensity in young red wines . In the hotter 2020 vintage, the total flavonols in grape berries were increased in D4 fruit compared to other treatments . This increased berry flavonol content was transmissible during winemaking, as D4 wines also showed the highest total flavonols with similar concentrations as C0 wines in 2020. TPI was also enhanced in D4 wines. As such, this increased the abundance of cofactors in the wine matrix. Thus, improved color intensity documented in D4 wines in both vintages could be due to the enhancement of absorbance from increased flavonol content by reducing thermal degradation in the vineyard . In the cooler 2021 growing season, shade films produced wines with less flavonols than C0, but greater anthocyanin content, thus leading to improved color intensity in D4 wines. The increase of phenolic cofactors in D4 wines not only enhanced color and hue, but also led to a higher percentage of polymeric anthocyanins when compared to other shade treatments. Phenolic and polyphenolic compounds from grape skins and seeds can form polymeric pigments in wine with anthocyanins. These polymeric anthocyanins are more stable than monomeric anthocyanins and help to stabilize wine color. This occurs as the proportion of monomeric anthocyanins decreases, leaving color to be maintained by polymeric anthocyanins . Across both vintages, the percentage of polymeric anthocyanins was maximized in D4 wines, indicating that these wines may have greater aging potential than wines from C0 and other shading treatments.In the present study, partial solar radiation exclusion modified the composition of anthocyanins in wine. Partial solar radiation exclusion resulted in increased anthocyanin glycosides in wine from shade film treatments except for D4 wines in 2020.

In 2021, D4 consistently showed the lowest cluster temperatures post-veraison and as a result, demonstrated the highest concentration of glucosides in resultant wines. Excessive berry temperatures post-veraison in both vintages led to C0 fruit with reduced total anthocyanin content at harvest and this carried over into resultant wines . The reduction of near-infrared radiation by at least 15% produced a cluster temperature conducive to anthocyanin accumulation, as these compounds are susceptible to thermal degradation above 35°C . When comparing total anthocyanin and flavonol concentrations between 2020 and 2021, regardless of treatment, 2020 wines had anthocyanin and flavonol concentrations six to seven times less than those in 2021 wines. As flavonoids are susceptible to thermal degradation, this drastic difference in total flavonoid concentrations may be attributed to hotter vintage air temperatures in 2020 compared to 2021. Previous works show berry sunlight exposure to alter the composition of anthocyanins, such as the proportion of acetylated and coumarylated forms . Modulation of acylated, methylated, and hydroxylated forms of anthocyanins result from the synergistic effect of solar radiation exposure and the coupled increases in berry temperature . Generally, high berry temperatures resulting from increased solar exposure results in increased acylated anthocyanins in the grape berry, particularly coumarylated forms . Also, high temperatures result in accumulation of highly methylated anthocyanins such as malvidin derivatives, as these compounds are less likely to degrade than their counterparts . In 2020, D1 and D5 wines demonstrated highest concentrations of acetylates, coumarylates, and methylated anthocyanins compared to C0 wines. While D1 and D5 treatments demonstrated cluster temperatures less than those from C0 treatments , the concomitant thermal degradation of total anthocyanins in C0 treatments proved to negate any modulation towards acylated or methylated forms in resultant wines.

Similarly in 2021, C0, D1 and D5 wines exhibited reduced acylation compared to D4 wines. Again, while D4 consistently exhibited less intense cluster temperatures, the thermal degradation in more exposed treatments eclipsed any identifiable acylation modulation from hot growing conditions. Acylated anthocyanins are more stable compounds and provide color stability and increase blueness in wine . However, an increase in methylated anthocyanins will lead to redder hues in wine . Therefore, the improvement in acylated and methylated anthocyanin content due to partial solar radiation exclusion may enhance color perception in young red wines through color stabilization and alteration of wine hue. Likewise, anthocyanin hydroxylation is also directly influenced by temperature and solar radiation exposure. Previous studies on berry exposure utilizing UV selective shade nets as well as leaf removal, demonstrated anthocyanin tri-hydroxylation increases with increasing berry temperature . Increases in tri-hydroxylation are driven by accumulation of malvidin derivatives and the temperature sensitivity of F3’H, the catalyzing enzyme for 3’- hydroxylated anthocyanin biosynthesis . The highest ratio of tri- to di-hydroxylated anthocyanins in 2020 C0 wines were driven by higher concentrations of 3-p-coumaroyl-glucoside derivatives of delphinidin, petunidin and malvidin, despite the ratio of tri- to di-hydroxylated anthocyanins being unaffected at harvest in the grape berry in 2020 . Among shade film treatments in 2020, the reduction of UV light exposure, was the determining factor in anthocyanin hydroxylation patterns rather than berry temperature. Previous shade net studies at the experimental site showed a reduction in UV radiation with black-40% and blue-40% shade nets led to higher anthocyanin tri-hydroxylation in the grape berry compared to control vines at harvest . With the reduction of UVB and UVC radiation in D4 and D5 vines, anthocyanin tri-hydroxylation was reduced, regardless of temperature. Ultimately, the upregulation of F3’H from sun exposure could be negated by the reduced catalytic activity of this enzyme under high temperatures experienced in 2020. In the cooler 2021 vintage, the ratio of tri- to di-hydroxylated anthocyanins was unaffected, due to non-significant effect of shade films on acetylated anthocyanins. Ultimately, increased tri-hydroxylation in young red wines will also impact wine hue, resulting in more purple wines . Flavonols in the grape berry skin act as photoprotectants and are strongly induced by ultraviolet radiation . Flavonol composition in the grape berry can be used to determine overexposure, raspberry container specifically by quantifying the molar abundance of kaempferol. C0 berries in this study were shown to be overexposed by surpassing the previously described threshold of approximately 7% molar abundance of kaempferol . In both years of the study, flavonol composition in grape berries was maximized in C0 fruit, but D4 and D5 fruit contained the most flavonols across the shade films with minimal thermal degradation of the compounds on the vine. Likewise in both winevintages, flavonol concentration was modulated by UV radiation exposure, proportional to the amount of UV radiation transmitted to the grapevine. Of the wines produced from shade films treatments, D4 allowed for the most UV transmission while subsequently reducing near infrared transmission by approximately 15%. These light conditions ultimately optimized flavonol content in D4 wines compared to the other shade treatments from both wine vintages. As such, this demonstrated the transmissibility of berry composition under shade treatments to directly improve wine flavonoid profiles. For hot viticulture regions, photo selective solar radiation exclusion provides a strategy to improve not only flavonoid profile but also wine color intensity through copigmentation with anthocyanins.

C6-alcohols such as 1-hexanol and -2-hexen-1-ol are often found in wines as fermentation products. These compounds are derived from microbial mediated cleavage of the C-C double bonds in linoleic and linolenic acids, by lipoxygenase and alcohol dehydrogenate enzymes in yeast . Compounds such as 1-hexanol and -2-hexen-1-ol are associated with aromas such as cut grass, green, fat, and herbaceous aromas and their OAV thresholds are 8000 and 400 ug/L, respectively . The effect of shade films on C6-alcohols was evident in both years; however, there was a yearly effect on which alcohol was altered by the treatment. In 2020, -2- hexen-1-ol was the lowest in D4. In 2021, -2-hexen-1-ol was unaffected by shade films, while 1-hexanol was highest in C0, D4 and D5. Although there was a statistical difference in C6 alcohols, the differences were not large enough between C0 and treatments to cross the OAV thresholds for these compounds. Increases of C6-alcohols in C0, D4, and D5 wines may be explained by solar radiation overexposure in the treated clusters. L. He etal. reported higher linoleic and linolenic acid biosynthesis with leaf removal at veraison. Subsequently, fruit exposed to increased solar radiation had elevated precursors for C6-alcohol production during yeast metabolism. Additionally, L. He et. al. showed higher initial concentration of C6-alcohols in grape berries from leaf removal treatments due to modulation of the volatile compound metabolome and transcriptome in grape berries exposed to sunlight under dry-hot conditions. Therefore, in our experiment which has similar climatic conditions to L. He et. al. , fruit from shade films with higher percentages of UV radiation may have both an increase in linoleic and linolenic acids to act as C6-alcohols aromas precursors and increased C6- alcohols in the exposed grape berries. Ultimately, overexposure of the grape berry led to more green and grassy aromas in wine, which may lead to an unripe perception of these wines. These compounds are generally pleasant aromas including mushroom, roses, honey, candy, and fruity notes. Of these compounds, shade treatments increased isoamyl alcohol concentration in 2020 and benzyl alcohol concentration in wines from both vintages. Isoamyl alcohol is associated with solvent and cheese aromas and, while benzyl alcohol is characterized as being citrusy and sweet . The odor active thresholds for these compounds are 30000 μg/L and 10000 μg/L, respectively . In 2020, C0 had the lowest concentration of isoamyl alcohol in wines. The effect of shading on the concentration of isoamyl alcohol in wines varies in literature . In hot growing regions, 75% of total solar radiation exclusion with black polyethylene canopy side shade nets resulted in wines with reduced isoamyl alcohol compared to the uncovered control vines . However, this experimental site was in a region that received approximately 704.5°C less growing degree days than the present experimental site in the hotter 2020 season, and 514.1°C growing degree days less than the cooler 2021 season. In the study by Lu et al. 2021, reduced solar radiation exposure in a cooler growing region may have resulted in reduced isoamyl alcohol in shaded fruit. When cluster temperatures exceed 42°C in exposed vines, there is a reduction in isoamyl alcohol in resultant wines compared to wines produced from fruit under red and black shade nets . With cluster temperatures of C0 fruit exceeding 42°C, excessive cluster temperatures may be prompting the reduction in isoamyl alcohol and overall wine fruitiness from those produced from overexposed clusters. However, while there was a statistical difference in isoamyl alcohol concentrations between C0 and treatment wines, the effect was not large enough to exceed the OAV threshold for this compound . Shade films affected the ester composition predominantly in 2020 wines.

The data from the Napping test were digitized by writing in a table, for each product, its X-coordinate and its Y-coordinate on the sheet. The origin was placed on the left bottom corner of the sheet.The chemical and sensory data of the wines were analyzed by multivariate analysis of variance , with the factors as the wines and replicates, and frequency distributions were analyzed by the Chi-square test; all statistical analyses were completed using Statgraphics Centurion . Principal component analysis was performed using XLSTAT v. 2018.3 ; partial least square regression analysis was performed using Unscrambler . A multiple factor analysis in which each subject of the Napping® panel constitutes a group of two un-standardized variables was performed using XLSTAT. The typicality scores of the second table and the Color scores of the third table were considered as two sets of 11 + 11 supplementary variables: They do not intervene in the axes construction, but their correlation coefficients with the factors of MFA are calculated and represented as in a usual PCA. Descriptive Analysis data were analyzed by MANOVA, to check overall differences among the products for aroma, taste, and mouthfeel terms. Following a three-way ANOVA with the factors wine, judge, and replicate as well as their two-way interactions, Fisher’s LSD test was used to detect differences among wines for the separate attributes. In those cases, where the effect of the wine was significant, but one of the interaction terms included wine as a factor, a pseudo-mixed model was applied. Here, a new F-value was calculated with the mean sum of squares from the significant interaction as an error term for the factor wine. The significance level for all statistical tests was set to p < 0.05. The chemical eligibility profile of the wines was represented by the standard chemical parameters , color indices and polyphenol composition.

The chemical data were elaborated using the PCA, growing blueberries and the results were reported in Figure 1a,b. Figure 1a shows the observations on a two-dimensional map. Figure 1b shows the correlationcircle and the projections of the initial variables in the factors space. The first two dimensions accounted for 57.90% of the total variance. The first dimension separated the wines between Italy and California based largely on the polyphenol composition. According to the squared cosines of the variables for the two dimensions, it was possible to determine that on the first dimension , quercetin , gallic acid , myricetin , total phenols index , color intensity , polymeric phenols , hue , residual sugar , volatile acidity , and pH were the variables well linked to this axis. On the second dimension , samples were separated by anthocyanin , delfinidin-3-O-glucoside , peonidin-3-O-glucoside , malvidin-3-O-glucoside, and quercetin-3-O-galactoside composition . According to the importance of the above mentioned variables, the Italian wines on the right side of the plot were characterized by the polymeric phenols, monomeric anthocyanins , color intensity, and total phenols index. The Californian wines on the left side of the plot were instead characterized by hue, residual sugar, pH, volatile acidity, malvidin-3-O-glucoside, and quercetin. The two ellipses defined the interval of confidence and helped to evidence a better separation between wines in the two regions. The chemical identity profile of the Sangiovese wines was represented by the volatile compounds originating in the grape and by the alcoholic and malolactic fermentations . The data were elaborated using the PCA, and the results were reported in Figure 2a,b. Figure 2a shows the observations on a two-dimensional map. According to the squared cosines for the variables on the two axes , the volatiles that were well linked to the first dimension were ethyl octanoate , octanoic acid , ethyl butanoate , ethyl decanoate , isoamyl acetate , 4-terpineol , and β-phenylethanol , while compounds on the second dimension were β-phenethyl acetate , TDN , 3-methylbutan-1-ol , isoamylbutanoate , and β-damascenone . Wines were separated according to the region of origin along the first dimension. In particular, most of the Californian wines were located on the right side of the plot described by volatile compounds such as esters , acetates and fatty acids .

On the left side of the plot, the Italian wines were characterized mostly by varietal volatile compounds such as terpenes β-citronellol, β-linalool, 4-terpineol, α-terpineol and norisoprenoids . However, the wines from the two different origins were not completely separated by the identity profile as evidenced by the overlapping confidence intervals of the two ellipses . Using Descriptive Analysis, the panel of trained judges described the sensory attributes of the Italian and Californian wines. Figure 3a,b shows the distribution of the wines according to the sensory eligibility and identity descriptors . Only significant descriptors were used for the PCA, and 79.30% of the total variance was explained by the first two factors/dimensions. One of the main objectives of this study was to examine intrinsic quality of the samples, evaluating how chemical differences in wines from Italy and California, in terms of eligibility and identity profiles , could reflect on the sensory perception of wines. In this context, the chemical eligibility profile of the wines was represented by the standard chemical parameters , color indices and polyphenols composition, while the chemical identity profile was represented by the volatile compounds originating in the grape and by the alcoholic and malolactic fermentations . The experimental data showed that the Sangiovese wines from Italy and California resulted in differences mostly for chemical eligibility profile. In particular, it was very evident that the Italian and Californian wines differed in their color indices and polyphenol composition . In fact, the Italian wines were higher in polyphenols compounds and in color intensity. These results were in agreement with the chemical characterization of Sangiovese wines from Italy and California for the 2016 harvest where the Italian wines resulted in higher color intensity and total phenols index compared to the Californian ones, that showed instead a higher hue. The values for these indices were consistent with other findings for Sangiovese wines. The differences in color indices were better explained by the polyphenols compounds of the wines that resulted in higher amounts for the Italian wines. They showed higher amounts of pigmented polymers and monomer anthocyanins . Sangiovese red grape is considered a variety with a neutral aroma since the total amount of terpenes is lower than 1 mg/L, and this variety is not dependent upon monoterpenes for its varietal flavor. In the Sangiovese pulp and skin some norisoprenoids precursors such as TDN, riesling acetale, damascenone, and vitispirane are detected. The above varietal volatile compounds were determined in both Italian and Californian wines indicating that the varietal aspects of the Sangiovese grape were maintained in both regions. Important differences were instead evidenced in wines from both regions according to the fermentative volatile compounds. The Californian wines were richer in the composition of these fermentative volatiles than the Italian wines confirming the trend observed for the same regions for the 2016 vintage. Significant differences for volatiles between the two regions were reported in Table S2 as supplementary material.

Based on the chemical differences in the composition of the wines from the two regions, we further explore how intrinsic quality, in terms of chemical differences, could be reflected on eligibility and identity sensory profiles of the wines. Moving to the perceived quality, square plant pots the second target of the study was to see how Tuscan wine experts perceived the peculiarity/typicality of the Sangiovese wines from Italy and California and to link the sensory descriptors that might be associated with the wines’ typicality. The sensory profiles of Californian and Italian samples were separated from each other, and the analysis of the correlation with the descriptive attributes allows interpreting this separation in terms of differences of both eligibility and identity profiles. The Californian samples were correlated to the identity attributes Bell Pepper, Cherry, Red Berries, Citrus, Honey. The attributes Barnyard, Earthy and Rubber were correlated to 4I and 5I wines, while there was not any correlation with the Californian wines. Given that all the samples were checked for the defects before all the sensory tests, this contrast seemed to describe a freshness range, for which varietal aromas were perceivable in some samples , while in other they were hidden by some typical aromas of a full-developed wine . The eligibility profile underlines this separation, with the samples on the left side of Figure 3a correlated to Sweetness that, even if associated to Alcohol and Burning/Hot, elicits a softer sensation respect to the Astringency and Sour of the Italian ones on the right side. The perceived quality was studied by the Napping and typicality test. The Napping test results showed that the Californian and Italian wines were clearly separated, evidencing that the two kind of wines were perceived differently for the gustative and olfactive characteristics. Despite of that, the results of the typicality evaluation did not show the same clear discrimination between the wines from the two regions: The average score of all the wines were very similar with the Californian wines slightly higher but not significantly different . Figure 4 showed the correlation between the distribution of the wine samples according to Napping X- and Y-coordinates: the subjects were positioned in the second, third and fourth quadrants of the graphic with a concentration of the higher scores in correspondence of the position of two Californian samples and one Italian . This result can be explained by the fact that, even if the expert subjects perceived differences among the wines, they did not associate them uniquely to typicality. Given the extensive training and experience of the experts, the lack of agreement among them can be interpreted not only as a variability of their opinion but also as an indication that from the point of view of perceived quality in terms of typicality of the Sangiovese wine, the experts viewed all of the wines as falling within the identity profile. At the same time, the distribution of the higher average scores denotes that typicality has been correlated to fruity and floral attributes, in opposition to Bell pepper, Barnyard, Rubber, and Earthy descriptors. In other words, the typicality of Sangiovese has been connected to the perception of the varietal characteristics that in this wine were related overall to fruity and secondly to floral.These findings were evidenced by the PLS prediction of the typicality by the identity sensory attributes such as Cherry and Red Berries. In the case of color evaluation, the experts more clearly separated the wines and overall the Italian wines had significantly higher scores. In fact, these samples, reflecting the chemical parameters, had a more intense color and overall a lower hue compared to the Californian ones. These results showed that the Sangiovese variety is recognizable even if grown abroad, very far from the original terroir of Italy and in particular in Tuscany. This is supported by the fact that the varietal volatiles were found in both wines from both countries, even if the Californian wines were more intense in fermentative volatiles than Italian wines were. Despite this, the main differences seemed related more to the intrinsic quality in terms of eligibility chemical and sensory profiles. Important and significant differences were found in wines for the polyphenol composition since Italian wines were higher in color intensity, tannins, monomeric anthocyanins, and pigmented polymers content. Consequently, they were perceived more intense in color and astringency. On the other hand, Californian wines were higher in alcohol content and pH and lower in titratable acidity compared to the Italian wines. These results reflected the eligibility sensorial perception of the wines in which the Italian wines tend to be more acidic, less sweet, and more astringent than their Californian counterparts. These results evidenced that the terroir seemed to influence the eligibility characteristics of the Sangiovese grape variety, in particular for the polyphenol composition. In Italy, wines with a designation of origin are subject to production requirements that dictate many aspects of wine production such as the maximum grape yields, alcohol level, irrigation, and other quality factors, before an appellation name may legally appear on a wine bottle label. In general, the US has the highest national average yields, at 6.5 tons/acre , and the only requirement to use the AVA name on the wine label is that 85% of the wine must have come from grapes grown within the geographical AVA boundaries.

The same miRNA candidate was described in the grape miRNA atlas also predicted to target several genes of DFR-like and one CCR. As for known miRNAs, several members of the miR395 family are differentially expressed at 19 ◦Brix and at harvest in Bolgheri and in both Bolgheri and Riccione, respectively, when comparing the two cultivars. Moreover, miR395f is differentially expressed also in CS at harvest between Montalcino and Bolgheri. This miRNA has been shown to target genes involved in Sulphate assimilation and metabolism , and hence it could be connected to flavonoid and stilbene pathways as suggested by Tavares et al. . miR399 family members are also differentially expressed in several comparisons: at 19 ◦Brix between Riccione and Bolgheri in CS and between Riccione and Montalcino in SG, plus in Montalcino between CS and SG. At harvest, miR399 are differentially expressed in SG in all the three comparisons among vineyards and in Riccione between CS and SG. miR399 is implicated in Phosphate homeostasis being rapidly up-regulated upon Pi starvation . miR399 regulatory network has been shown to be important in flowering time and was identified as a temperature-sensitive miRNA , however its characterization in fruit ripening is lacking, although intriguing. miR396 family members are known to be regulated during organ development, targeting Growth Regulating Factors and also in berry development , and we observed their modulation during berry ripening in our data as well, but more interestingly, drainage planter pot they are also differentially expressed between CS and SG in berries sampled in Bolgheri at 19 ◦Brix.

Finally, the investigation of the global relationships of different small RNA classes and miRNAs expressed in different grapevine cultivars, collected in different vineyards and developmental stages, suggests that although the vineyard may influence their profile of abundance it probably does in less proportion than developmental stage and cultivar. Somehow, this behavior would be expected because although the epigenetic state is dynamic and responsive to both developmental and environmental signals, small RNAs in general and even more miRNAs are well known to play numerous crucial roles at each major stage of plants development . The results here described are in agreement with those reported in the grapevine miRNA atlas , especially with respect to the clustering of berries according to their developmental stage, sustaining the idea that miRNAs influence organ identity and clearly separate green and ripened berries. Also, in the study of the grapevine transcriptome performed by Dal Santo et al. , they observed that other factors such as year and developmental stage had more influence on the gene expression, rather than the environment. Garden or English peas are hardy, cool season, vining annuals grown for their fresh immature green seeds and pods. Peas are classified in the Fabaceae family, which consists of approximately seven hundred genera and seventeen thousand species, with cosmopolitan distribution throughout the temperate, subtropical, and tropical zones of the world. Many species in this family are used as food, forage, timber, and dye plants. Peas are thought to have originated on the eastern rim of the Mediterranean into the mideast. Remains of 7,000- year-old carbonized seeds have been found in Switzerland. By the height of the Greek and Roman civilizations, peas were well established garden, field, and green manure crops. Although peas are not heavy yielders , they are well worth the effort in small gardens. A fresh garden pea’s taste is so far superior to its store-bought equivalent that it is in fact a different vegetable—sugar vs. starch, fresh and lively vs. dull and soggy. Along with spinach, peas usually herald the first working of the soil and planting in spring. If all goes well, sweetness and succulence await you 50 to 70 days after planting seeds. Because they need to be trellised, peas afford excellent opportunities for intercropping .

Once established, peas don’t require much work. They are able to grab onto the trellis and spread themselves out for greater exposed photosynthetic area and better air circulation to reduce the incidence of mildew. They are not very sensitive to weed pressure. In fact, weeding established pea patches can do more harm than good, as peas have numerous surface roots that are sensitive to disturbance.Cultivation. All peas are emphatically cool season crops. Optimally, they are direct sown when the soil temperature averages over 50° F. Sixty to eighty days of temperatures below 80° F are requisite for good production. Soil temperatures of 55°–75° F will yield germinating seedlings in 7–10 days. Overly wet and cold or wet and warm soil increases the percentage of pre-emergent rot. In fact, because pea seeds are large and can imbibe and hold so much water, allowing the soil to dry down significantly between waterings will reduce rot and ensure good germination. Soils. Good drainage is essential for vigorous growth. Early cropping favors sandy soils as they drain and warm more quickly than clays. Peas, as do most legumes, prefer a slightly acid to slightly alkaline soil pH. This higher pH range also provides for the high calcium needs of peas. Peas are intolerant of acid soils. Planting. Peas should be direct seeded or gently transplanted from speedling/plug trays. Seeds can either be drilled in rows or broadcast sown. Drills can be single or double rows 2–4 inches from the trellis to facilitate the tendrils finding the fence. Seeds should be sown heavily , as pea seeds generally have a moderate germination percentage even under ideal conditions. Thin to 8–12 seeds per foot if necessary. The general adage about covering seed two to three times its narrowest diameter applies here; seeds should be planted 1–1 1/2 inches deep, then gently tamped or watered in.

Pea seeds can also be thickly broadcast at 2–3 seeds per square inch, and raked in or covered with soil. Twiggy brush or one to two layers of horizontal netting creates the trellis for support. This broadcast method nets a higher yield per area but can increase incidence of powdery mildew due to restricted air circulation. Note that pea seed viability is relatively short under ideal circumstances. In most home garden situations seed will only last 1–3 years. When ordering pea seeds, think in 1/2 and 1 pound increments . Varietal selection is important as to plant height and time to maturation, but most importantly, pay attention to disease resistance. Basically, if a varietal description doesn’t tout or mention disease resistance, be a smart shopper and realize it probably has none. The more recent the varietal introduction, the more disease resistant it is. Unfortunately, the converse is true as regards heirloom varieties. Nutrients. Because legumes are capable of fixing nitrogen via association with soil bacteria, garden peas are mistakenly thought to need little or no supplemental nitrogen. The truth is that they fix very little nitrogen unless inoculated with the appropriate species of bacterium . They will also use most of the nitrogen they fix and thus don’t particularly enrich the soil for the following crop. Phosphorous is an important nutrient for early root development and to assist with flowering, fruiting and sugar development. Fortunately legumes are efficient at gathering and concentrating phosphorous. Fertilizing the peas prior to planting is optional on enriched or improved soils. A compost of chicken manure, mixed greens, and straw or leaves will boost nitrogen and phosphorous levels. Composts of brassicas and legumes will concentrate phosphorous and calcium. With a single or double row of peas on a trellis in the center of a 48-50-inch-wide raised bed, plant pot with drainage a crop of quick-maturing plants can be grown along the bed edges for more efficient use of space. These include — Planting Days to Crop method harvest baby spinach direct sown 20-30 days mature spinach direct sown 40-50 days cutting lettuces transplanted 20-30 day mature leaf or transplanted 40-50 days mini romaine lettuce butter lettuce transplanted 50-60 days arugula direct sown 20-30 days direct-seeded radishes direct sown 30-40 days Inoculation. Pea plant vigor and thus production is markedly increased when the seed is inoculated with the appropriate species of Rhizobium bacteria . These bacteria can be purchased in a powdered carrying agent from most seed catalogues and nurseries. To inoculate, simply dampen the seed, add powdered inoculate and mix until the seeds have a blackened, peppered look. Plant as soon as possible as the water activates the bacterial population and desiccation is harmful. Watering. Peas require 1–2 inches of water per week. They are intolerant of water stress ; stress will reduce plant size, decrease yield quality—resulting in tough, starchy peas—and severely shorten the length of cropping. Flowering and early fruit set are key times to ensure an even flow of water. While peas have a tap root that can penetrate up to 3 feet, most of the effective feeding roots range from just under the surface to 12–15 inches deep.

Once peas are established, and especially as they begin fruiting, they are subject to a fungal disease called powdery mildew. Overhead watering in conjunction with high humidity will bring on the disease. To help avoid the problem, either water overhead in the morning prior to a sunny stretch of weather so that the plants will dry out, or use drip tape or soaker hose around the base of the plants. Trellis or Fencing. All but the shortest varieties of peas need some sort of support. Although many varieties are advertised as self-supporting , this is not true. Fencing allows closer plant spacing , because the plants can spread out on the trellis or fence. Fencing also increases sunlight interception, minimizes disease, and facilitates easier picking. One age-old tradition for trellising peas is what the British refer to as “twiggy brush.” The branched prunings of last year’s growth from fruit trees inserted into the soil make an excellent, cheap, and somewhat artistic fence. The brush is usually good for two to three years. One- and two-inch chicken wire will also suffice. Unlike beans, peas aren’t a heavy plant or fruit, thus they don’t need as strong a fence. In fact, garden twine run vertically or woven between horizontal 2x4s makes a biodegradable/compostable trellis. String on a wooden A-frame also works. The important thing is to install the trellis prior to planting and to rotate it around the garden so as not to be tempted to repeat the crop in the same bed before two to three years have passed. Crop Establishment. Unless peas are ridiculously oversown, thinning is unnecessary. Spacing plants farther than 3–4 inches apart makes no sense, nor increases yield per foot. One weeding at the 3-inch stage usually keeps the peas ahead of the weeds. Because peas are so succulent, the less the crop is handled the less the physical damage. Even micro-breaks in the foliage can lead to an “invasion” of powdery mildew. Mulch. Mulching helps protect the surface roots from heat and desiccation, thus prolonging cropping as summer approaches. Harvesting. This is usually not a problem on a garden scale. To avoid harming the plants as you pick, hold the stem in one hand and pinch the pod off the vine just behind the calyx with the other hand.As the worldwide obesity epidemic continues to grow, the prevalence of type II diabetes is also rising to a projected 439 million of individuals globally by 2030. Of all obesity-related chronic conditions, diabetes is most strongly associated because of their similar symptomatic manifestations. Type II diabetes and obesity are both characterized by insulin resistance, glucose intolerance, hypoadiponectinemia, endoplasmic reticulum stress, and low-grade inflammation. Over 11% of the 34% of U.S. obese adults are reported to be diabetic in 2011.2 Obesity is generally thought to stem from a combination of genetic and environmental factors. Increased dietary consumption of fat and refined carbohydrates along with decreased physical activity contributes to excessive weight gain while underlying genetic dispositions may lead to differential clinical progression. It has become clear that modest weight reduction can improve glycemic control and alleviate insulin resistance as obesity is considered a modifiable risk factor for diabetes. Furthermore, the comorbidity of diabetes and obesity has been linked to liver and colon cancer risk, although the precise mechanisms remain unresolved.

An anticipated management solution to phenological shifts is planting later ripening and stress tolerant alternative varieties. Government response to climate change will determine the actions European growers are allowed to take to adapt to climate change, considering the current trials of alternative varieties planted in small diversity blocks in France as a positive example . Ancient varieties being tested in temperature gradient greenhouses in Spain for response to combination stresses of drought, heat, and elevated CO2 showed greater resiliency to stress and did not shift phenological timing, although this was a short-term experiment . In some cases, alternative varieties may be hybrid crosses between existing cultivars and later ripening varieties. However, hypothetical crosses between very late ripening varieties were modelled and still struggle to be late-ripening enough to endure the predicted 23-day shift and potential increase of 7°C expected by the end of this century for major wine grape growing areas . Alternative varieties can be identified by oenological and ecological principals that make them suitable candidates for replacing existing cultivars, such as flavor profile and ability to survive long term through stressful climate change conditions . The challenge of adapting new varieties is highlighted by current popular varieties struggling with increases in growing season temperatures , drainage collection pot however a combination of diversity block trials and greenhouse experiments will guide predictions of the best alternatives .

Our present knowledge of grapevine climate niches is limited relative to the vast diversity of cultivars . With California as an example, there are many potential late ripening varieties suitable as alternatives to early ripening Chardonnay that have yet to be tested in diversity blocks . Even clones can have a varied response to climate change variables . Varieties with heat and drought tolerance traits are a starting point for elevated CO2 studies, as we expand from understanding the mechanisms of change into exploring mitigation strategies. Exploring the vast diversity of grapevine using diversity plots is a straightforward ecological approach, which could be enhanced by evaluating the success of plants under several biotic and abiotic stresses predicted for the future. Many studies on the impacts of leaf removal suggest that manipulating canopy cover is an effective way to mitigate phenological shifts caused by climate change . Leaf removal at pre-bloom positively influences cell division in inflorescence, by reducing sugar transport and decreasing flower fertility, which mitigates cluster compactness . Not only can leaf removal aid in delaying phenology, but other positive impacts also include increasing acid to sugar ratio at harvest, increasing production of anthocyanins and flavonoids, and decreasing incidence of bunch rot disease . Ecologists generally study a system’s responses and interactions, and viticulturists need this system perspective for the challenges presented by climate change. Our understanding of the effects of elevated CO2 on the vineyard system is profoundly complicated by the interactive effects of other biotic and abiotic stressors. From an ecological perspective, long-term FACE studies are the most realistic predictors of response to elevated CO2.

Advocating for long-term agroecological studies is necessary to evaluate the top-down and bottom-up impacts of higher carbon availability on pest/disease interactions, grapevine growth and phenology dynamics, and the resulting quality of wine produced. Grapevine physiology will be impacted by elevated carbon dioxide, increasing temperatures, and extreme heat events during the growing season . FACE experiments highlight the necessity of water availability for grapevines to take advantage of increased carbon dioxide for productivity. Soil water availability impacts the opening of stomata, and in the case of Vineyard FACE, the vines had increased gs with more CO2 available . Grapevines may need more water under future climate conditions of elevated CO2 and temperature, while precipitation is expected to decrease in most of the wine growing regions of the world. Desiccation threatens vines through water loss from latent cooling under elevated temperature, resulting in higher cumulative water loss even when operating at higher water use efficiency. The modulating response of stomata documented across literature is dependent on the soil water availability and temperature regimes . In this synthesis, the varying levels of CO2, ambient temperatures, and duration of these experiments could have contributed to these contrasting results of stomatal behavior, as well as the conditions of the chambers and greenhouses, versus FACE infrastructure. Physiological response to abiotic stresses in future climate change conditions is likely to weaken grapevine, creating a vulnerability for biotic stresses such as pests. Overall, chewing pest pressure is anticipated to increase as carbon dioxide and temperature increase . It is unknown whether pest pressure can be compensated by the predicted increase in foliar growth and the effect of lower nutrient density on the populations of pests.

The growing season for grapes may require drastic changes in viticultural practices to manage pests, alleviate heat and drought stress, and predict harvest dates. Fungal infections are responsible for a majority of crop damage; therefore, it is critical to clarify if fungal infection will decrease in the future for predictions of grapevine yield. One of the biggest challenges for grape growers will be the shifts in phenological timing, with the potential for frost at early bud break, alterations in cluster formation and density, and compromising harvest with early maturation. Many of the short-term experiments described here did not find significant effects on phenology and yield, while long term studies account for acclimation and compounding effects of seasonal exposure to elevated carbon dioxide. Predictions of overall vineyard response to climate change are more accurate when experiments are field based, multi-seasonal, and combine the variables of water availability and temperature. Climate change is increasing the growing season temperatures in many of the world’s most important winegrape growing regions. According to the most recent IPCC Assessment Report, Climate Change 2021, global warming is expected to exceed 1.5°C – 2°C during this century . Warming caused by anthropogenic greenhouse gas emissions advances phenology in hundreds of plant species, with increased consequences for perennial crops . Climate warming has already altered the phenology of many plant species globally, including the phenology of valuable crop plants such as grapevine . Winegrapes, a globally important crop both economically and culturally, have become an important indicator of climate change, with well documented advancing phenology, shorter periods between phenological stages , and large inter-annual variability . Adapting to climate change has become a global priority, and the wine industry is likewise looking for more accurate predictive measures of phenology and strategies for future planting. Culturally and economically, grapevine is one of the most valuable crops in the world, evidenced by an annual production of 60 million tons of fruit , with varieties that have been cultivated for thousands of years, selected for color, flavor, and phenological timing . Grape growth and qualities are sensitive to growing season climate fluctuations, and there is a direct link between warming temperatures and early harvest dates . Earlier ripening forces farmers to harvest grapes at optimal sugar levels during warmer periods of the summer. Harvest should ideally occur later during a cooler period of the growing season after the berry has accumulated an appropriate balance of acids of sugars. Early harvesting decreases the quality of wine, round plastic pot evidenced by early ripening significantly altering berry chemical composition . Higher year-round temperatures impact varieties with chilling requirements, such as California’s premiere wine grape, Chardonnay . Globally, there have been shifts of 1-2 weeks for winegrape growing regions . In Europe, the growing season has lengthened by about 11 days over the last 30 years, which will impact grape berry and wine quality . Early bud burst threatens frost damage during volatile Spring temperatures . At present, the winegrape crop in Bordeaux has a month earlier harvest than it did 50 years ago . Models of warming indicate that increases in temperature are not uniform globally and that warming has increased in the major wine growing areas of California and Western Europe more than South America and Australia during the past 50 years . The phenological shifts resulting from growing season temperature increases are documented internationally, and models predicting phenology using temperature are becoming more precise . A multitude of studies both observational and experimental have identified an acceleration of phenology and decrease in periods between stages in response to warming growing seasons , but some show trends of the intervals between each stage widening . Previous grapevine modeling which quantified relative sensitivity of many varieties combined records of phenology across variable microclimates and conditions . Comparing phenological timing from different vineyards done does not capture the influence of the microclimate and microhabitat; elevation, management, soil type, and a multitude of other environmental factors can impact flowering time . The ampelography vineyard at University of California Davis allows for attributing the variation in phenology to the specific sensitivity of cultivars to changes in climate, rather than soil type, irrigation method, pruning, or other major sources of variability found when comparing multiple vineyards.

Temperature is the main driver of phenological development for grapes; heat accumulation impacts the biochemistry important for cell growth . A study of 15 cultivars in Australia documented a plateau in growth between 22-29°C . For many plant species, higher temperatures can stagnate growth, and we expect that some varieties of grapevine would be sensitive to temperatures greater than 40°C . In extreme cases, beyond inducing premature veraison, heat stress will cause loss of berries, inactivate enzymes, and reduce development of flavors critical for wine quality . We integrate into our models a measure of extreme heat to determine its effect on veraison, the stage most likely impacted by these events. In this study, we examined variability in the phenological responses of 137 varieties of Vitis vinifera over a 5-year period. We examined variability in the timing, in terms of growing degree days, of the three major phenological stages: budburst, flowering, and veraison. Our data provide an updated reference to the last major study of variety-level phenological responses in California, which examined 114 varieties nearly 40 years ago . We also compare traditional Vitis vinifera species with hybrids grown at the University of California Davis, originally cultivated by Harold Olmo. Overall, this study offers a comprehensive look at international varieties planted in California their relative phenological response to climate. This study aims to evaluate a wide range of cultivars to identify regions with lower sensitivity to climate change that may be used in adaptation, either through breeding or planting as alternatives. The UC Davis ampelography learning vineyard has been developed over the past decade to include approximately 300 international varieties planted adjacent to the Viticulture and Enology academic building. The vines are planted in groupings by geographic origin, for the purpose of teaching. The vines are trellised using vertical shoot position , with regular irrigation, and are treated throughout the growing season with sulfur sprays for pests and disease. The current study of phenology has been tracking over 130 varieties for over four years and measures the response of the varieties through three main phenological stages: budburst, flowering, and veraison. The phenological data has been collected from UC Davis starting in 2014, continued through 2019. For each of 137 varieties, we recorded the timing of three major phenological stages: Budburst, Flowering, and Veraison. The same individuals were monitored for 5 years. For each vine, three positions on the cordon were chosen at the start of each season before budburst, following the previous year’s recorded positions unless damage had occurred, in which case a nearby cordon was chosen . The primary buds from each two-bud spur were chosen at the most basal position. The three buds were tracked through each phase, treated as technical replicates averaged for an overall estimate for each individual vine. Each vine is a biological replicate, and two vines per cultivar were measured. The timing of budburst was recorded as stages 1-13 , based on the modified Eichhorn–Lorenz stage of the three positions monitored for each vine . The EL scale describes the phenological stages of grapevine and categorizes the stages as follows: budbreak, shoot development, flowering, fruit set, berries pea-sized, veraison, and harvest . Flowering was monitored from these same shoot positions, and once clusters started to develop, they were marked with flagging tape.

The BIA also established a GIS branch that encourages tribes and offers advice on tribal GIS development-although recent funding cutbacks have hampered this effort-and has stockpiled a considerable amount of tribal GIS data in their own library.68 Partly in response to these developments and partly because many Indian communities are deeply suspicious of the BIA-backed tribal governments where GIS managers are housed, a consortium of tribes in the northern Plains and another in the Rio Grande corridor have limited BIA and other federal agencies’ access to some of their databases, declaring some of their GIS proprietary in an attempt to protect sensitive and sacred geographical information. These and other longstanding problems associated with the allocation of political authority in Indian Country caused one geographer to raise questions about the path of GIs development, especially its transformative powers, surveillant capabilities, and political uses.69 Through experience working with GIS, many have come to see it as a contradictory technology that can both empower and marginalize people and communities. Arguments about the social impacts of GIS have grown in recent years, and a debate has surfaced in geography under the heading “GIS and Society.” One of the more interesting proposals emerging from that debate, and worth considering in Indian Country, is for development of “community-integrated GIS that focus on local empowerment through community, not government, 10 liter pot control of and access to digital geographic information. We think this review signals the arrival of geography as a small but important participant in American Indian studies.

Geographers are helping to illuminate the complexity and refinement of environmental modifications made by early Indians and perpetually revise our knowledge of these matters in virtually every region of the continent. They also are busy telling mainstream society that water is a vital cultural source-not just a scarce but necessary physical commodity-with the intent of altering the allocation and cost-benefit models used in managing it. Geographers continue to document land fraud through dispossession research in both historical and contemporary periods, sitting in courtrooms as expert witnesses to do so, and by trying to educate other geographers still steeped in traditions of seeing Indian land claims as an insignificant “interest” competing against “higher” uses. Geographers also continue to assert the centrality of land and place in Indian identity and to explore how attachments to place are manipulated by both individuals and the institutions that would control them. They continue to deconstruct the imprint of European and Euro-North American colonization and to unpack the sounds and silences in historical and contemporary maps and GIS, in part to promote more culturally sensitive applications of technology. Geographers are working with planners and tribal leaders to develop models for cooperative planning for future economic development. Increasingly, they are reflecting on their own positions as privileged researchers, teachers, and consultants. Finally, they are teaching all this to their students. By no means are we implying that everything is just fine in geography. For example, there is a sense among many AISG members that we can and should become more active and involved in issues of importance to Native people throughout North America, to the point of adopting advocacy stances more frequently.

Some of the work cited here leads in that direction, especially the accomplishments of those working on sources and development. However, much of the other work often seems to hold Indians at arm’s length. This may be because many geographers still look askance at colleagues who take on advocacy roles, believing that the mask of apolitical objectivity so often donned in the past is still worth wearing. Perhaps some are justified in their aloofness, preferring the detachment afforded by theoretical questions, or the solitude available in archives and libraries. On the other hand, theoretical and empirical work on material and ideal landscapes, identities, and represen- tations, and the research on historical and contemporary cartographies are among the fastest growing and most intellectually active areas of the field. It is also certain that there is much more that is needed in the field: historical studies exploring continuities in land use and governance for land claims; land use and place-name mapping and GIS for preservation of cultural sources; examinations of the spatial basis for self-governance and self determination to support sovereignty; critical approaches to the role of space and place in the social construction of “Indians” via public perceptions, legislative agendas, corporate intentions, and classroom teaching; continued work in deconstructing colonial legacies and postcolonial discourse in the effort to achieve genuine polyvocality; and analyses of the health care distribution system of the majority and its relationship to alternative medical systems available through local cultural practices. It is encouraging to see a diversity of topics and approaches being engaged with enthusiasm. And in all of it geographers increasingly realize that it is no longer possible to remain completely indifferent about the politics of their own research when studying North America’s Native communities, places where research, self-determination, and sovereignty now typically go hand in hand. Grapevine berry ripening can be divided into three major stages. In stage 1, berry size increases sigmoidally.

Stage 2 is known as a lag phase where there is no increase in berry size. Stage 3 is considered the ripening stage. Veraison is at the beginning of the ripening stage and is characterized by the initiation of color development, softening of the berry and rapid accumulation of the hexoses, glucose and fructose. Berry growth is sigmoidal in Stage 3 and the berries double in size. Many of the flavor compounds and volatile aromas are derived from the skin and synthesized at the end of this stage. Many grape flavor compounds are produced as glycosylated, cysteinylated and glutathionylated precursors and phenolics and many of the precursors of the flavor compounds are converted to various flavors by yeast during the fermentation process of wine. Nevertheless, there are distinct fruit flavors and aromas that are produced and can be tasted in the fruit, many of which are derived from terpenoids, fatty acids and amino acids. Terpenes are important compounds for distinguishing important cultivar fruit characteristics. There are 69 putatively functional, 20 partial and 63 partial pseudogenes in the terpene synthase family that have been identified in the Pinot Noir reference genome. Terpene synthases are multi-functional enzymes using multiple substrates and producing multiple products. More than half of the putatively functional terpene synthases in the Pinot Noir reference genome have been functionally annotated experimentally and distinct differences have been found in some of these enzymes amongst three grape varieties: Pinot Noir, Cabernet Sauvignon and Gewürztraminer. Other aromatic compounds also contribute significant cultivar characteristics. C13-norisoprenoids are flavor compounds derived from carotenoids by the action of the carotenoid cleavage dioxygenase enzymes. Cabernet Sauvignon, Sauvignon Blanc and Cabernet Franc are characterized by specific volatile thiols and methoxypyrazines. Enzymes involved in the production of these aromas have been recently characterized. Phenolic compounds play a central role in the physical mouthfeel properties of red wine; recent work relates quality with tannin levels. While the grape genotype has a tremendous impact on tannin content, the environment also plays a very large role in grape composition. The pathway for phenolic biosynthesis is well known, but the mechanisms of environmental influence are poorly understood. Ultimately, there is an interaction between molecular genetics and the environment. Flavor is influenced by climate, topography and viticultural practices. For example, water deficit alters gene expression of enzymes involved in aroma biosynthesis in grapes, which is genotype dependent, and may lead to increased levels of compounds, such as terpenes and hexyl acetate, 10 liter drainage collection pot that contribute to fruity volatile aromas. The grapevine berry can be subdivided into the skin, pulp and seeds. The skin includes the outer epidermis and inner hypodermis . A thick waxy cuticle covers the epidermis. The hypodermal cells contain chloroplasts, which lose their chlorophyll at veraison and become modified plastids; they are the sites of terpenoid biosynthesis and carotenoid catabolism. Anthocyanins and tannins accumulate in the vacuoles of hypodermal cells. Pulp cells are the main contributors to the sugar and organic acid content of the berries. Pulp cells also have a much higher set of transcripts involved in carbohydrate metabolism, but a lower set of transcripts involved in lipid, amino acid, vitamin, nitrogen and sulfur metabolism than in the skins. Concentrations of auxin, cytokinins and gibberellins tend to increase in early fruit development of the first stage. At veraison, these hormone concentrations have declined concomitant with a peak in abscisic acid concentration just before veraison.

Auxin prolongs the Stage 2 lag phase and inhibits anthocyanin biosynthesis and color development in Stage 3. Grapevine, a non-climacteric fruit, is not very sensitive to ethylene; however, ethylene appears to be necessary for normal fruit ripening. Ethylene concentration is highest at anthesis, but declines to low levels upon fruit set; ethylene concentrations rise slightly thereafter and peak just before veraison then decline to low levels by maturity. Ethylene also plays a role in the ripening of another non-climacteric fruit, strawberry. ABA also appears to be important in grape berry ripening during veraison when ABA concentrations increase resulting in increased expression of anthocyanin biosynthetic genes and anthocyanin accumulation in the skin. ABA induces ABF2, a transcription factor that affects berry ripening by stimulating berry softening and phenylpropanoid accumulation. In addition, ABA affects sugar accumulation in ripening berries by stimulating acid invertase activity and the induction of sugar transporters. It is not clear whether ABA directly affects flavor volatiles , but there could be indirect effects due to competition for common precursors in the carotenoid pathway. Many grape berry ripening studies have focused on targeted sampling over a broad range of berry development stages, but generally with an emphasis around veraison, when berry ripening is considered to begin. In this study, a narrower focus is taken on the late ripening stages where many berry flavors are known to develop in the skin. We show that that the abundance of transcripts involved in ethylene signaling is increased along with those associated with terpenoid and fatty acid metabolism, particularly in the skin.Cabernet Sauvignon clusters were harvested in 2008 from a commercial vineyard in Paso Robles, California at various times after veraison with a focus on targeting °Brix levels near maturity. Dates and metabolic details that establish the developmental state of the berries at each harvest are presented in Additional file 1. Berries advanced by harvest date with the typical developmental changes for Cabernet Sauvignon: decreases in titratable acidity and 2- isobutyl-3-methoxypyrazine concentrations and increases in sugar and color . Transcriptomic analysis focused on four harvest dates having average cluster °Brix levels of 22.6, 23.2, 25.0 and 36.7. Wines made in an earlier study from grapes harvested at comparable levels of sugars or total soluble solids to those in the present study showed clear sensory differences. Six biological replicates, comprising two clusters each, were separated into skins and pulp in preparation for RNA extraction and transcriptomic analysis using the NimbleGen Grape Whole-Genome Microarray.A note of caution must be added here. There are high similarities amongst members in certain Vitis gene families , making it very likely that cross-hybridization can occur with probes on the microarray with high similarity to other genes. We estimate approximately 13,000 genes have the potential for cross-hybridization, with at least one probe of a set of four unique probes for that gene on the microarray potentially cross-hybridizing with probes for another gene on the microarray. Genes with the potential for crosshybridization have been identified and are highlighted in light red in Additional file 2. The rationale to include them is that although individual genes can not be uniquely separated, the probe sets can identify a gene and its highly similar gene family members, thus, providing some useful information about the biological responses of the plant. An additional approach was taken, removing cross-hybridizing probes before quantitative data analysis . Many of the significant genes were unaffected by this processing, but 3600 genes were completely removed from the analysis. Thus, it was felt that valuable information was lost using such a stringent approach. The less stringent approach allowing for analysis of genes with potential crosshybridization was used here in the rest of the analyses. To assess the main processes affected by these treatments, the gene ontologies of significantly affected transcripts were analyzed for statistical significance using BinGO. Based on transcripts that had significant changes in abundance with °Brix level, 230 biological processes were significantly over represented in this group . The three top over represented processes were response to abiotic stress, biosynthetic process, and response to chemical stimulus, a rather generic set of categories.

The closest imaginable analog of the tBLG/hBN Chern magnet in this system is one in which interactions favor the formation of a valley-polarized ferromagnet, at which point the finite Chern number of the valley subbands would produce a Chern magnet. This was widely assumed to be the case at the time of the system’s discovery. There is now substantial evidence that this system instead forms a valley coherent state stabilized by its spin order, which would require a new mechanism for generating the Berry curvature necessary to produce a Chern magnet. In general I think it is fair to say that the details of the microscopic mechanism responsible for producing the Chern magnet in this system are not yet well understood. In light of the differences between these two systems, there was no particular reason to expect the same phenomena in MoTe2/WSe2 as in tBLG/hBN. As will shortly be explained, current-switching of the magnetic order was indeed found in MoTe2/WSe2. The fact that we find current-switching of magnetic order in both the tBLG/hBN Chern magnet and the AB-MoTe2/WSe2 Chern magnet is interesting. It may suggest that the phenomenon is a simple consequence of the presence of a finite Chern number; i.e., that it is a consequence of a local torque exerted by the spin/valley Hall effect, which is itself a simple consequence of the spin Hall effect and finite Berry curvature. These ideas will be discussed in the following sections. In spin torque magnetic memories, electrically actuated spin currents are used to switch a magnetic bit. Typically, hydroponic vertical garden these require a multi-layer geometry including both a free ferromagnetic layer and a second layer providing spin injection.

For example, spin may be injected by a nonmagnetic layer exhibiting a large spin Hall effect, a phenomenon known as spin-orbit torque. Here, we demonstrate a spin-orbit torque magnetic bit in a single two-dimensional system with intrinsic magnetism and strong Berry curvature. We study AB-stacked MoTe2/WSe2, which hosts a magnetic Chern insulator at a carrier density of one hole per moir´e superlattice site. Magnetic imaging reveals that current switches correspond to reversals of individual magnetic domains. The real space pattern of domain reversals aligns with spin accumulation measured near the high Berry curvature Hubbard band edges. This suggests that intrinsic spin or valley Hall torques drive the observed current-driven magnetic switching in both MoTe2/WSe2 and other moir´e materials. The switching current density is significantly less than those reported in other platforms, suggesting moir´e heterostructures are a suitable platform for efficient control of magnetic order. To support a magnetic Chern insulator and thus exhibit a quantized anomalous Hall effect, a two dimensional electron system must host both spontaneously broken time-reversal symmetry and bands with finite Chern numbers. This makes Chern magnets ideal substrates upon which to engineer low-current magnetic switches, because the same Berry curvature responsible for the finite Chern number also produces spin or valley Hall effects that may be used to effect magnetic switching. Recently, moir´e heterostructures emerged as a versatile platform for realizing intrinsic Chern magnets. In these systems, two layers with mismatched lattices are combined, producing a long-wavelength moir´e pattern that reconstructs the single particle band structure within a reduced superlattice Brillouin zone. In certain cases, moir´e heterostructures host superlattice minibands with narrow bandwidth, placing them in a strongly interacting regime where Coulomb repulsion may lead to one or more broken symmetries.

In several such systems, the underlying bands have finite Chern numbers, setting the stage for the appearance of anomalous Hall effects when combined with time-reversal symmetry breaking. Notably, in twisted bilayer graphene low current magnetic switching has been observed, though consensus does not exist on the underlying mechanism. Although these magnets occur in an atomic crystal, they are composed entirely of electrons we have forced into the system with an electrostatic gate, and as a result we can expect their magnetizations to be considerably smaller than fully spin-polarized atomic crystals. We will use the nanoSQUID microscope to image these magnetic phases. An optical image of the ABC trilayer graphene device used to produce data for the publications is presented in Fig. 7.5A. A black dashed lineoutlines the region we will be imaging using the nanoSQUID microscope. A nanoSQUID image of this region using AC bottom gate contrast is presented in Fig. 7.5B. This magnetic image was taken in the same phase in which we observe magnetic hysteresis, as presented in Fig. 7.4E. Clearly the system is quite magnetized; we also see evidence of internal disorder, likely corresponding to bubbles between layers of the heterostructure. We can park the SQUID over a corner of the device and extract a density- and displacement field-tuned phase diagram of the magnetic field generated by the magnetization of the device; this is presented in Fig. 7.5C. Electronic transport data of the same region is presented in Fig. 7.5D. The spin magnet has only a weak impact on electronic transport, but the valley ferromagnet couples extremely strongly to electrical resistance. The system also supports a pair of superconductors, including a spin-polarized one; these phases are subjects ofcontinued study. Capacitance data over the same region of phase space is presented in Fig. 7.5E. The first systems with nonzero Chern numbers to be discovered were systems with quantum Hall effects. Quantum Hall insulators behave a lot like Chern magnets but are generally realized at much higher magnetic fields, and Berry curvature in these systems comes from the applied magnetic field, not from band structure. The fact that resistance in these materials is an intrinsic property and not an extrinsic one had implications for metrology that were immediately obvious to the earliest researchers that encountered the phenomenon. All of these devices have resistances that depend only on fundamental physical constants, so a resistance standard composed of these materials need not obey any particular geometric constraints, and can thus be easily replicated. The case for quantum Hall resistance standards was strong enough for the the National Institute for Standards and Technology to rapidly adopt them, and today the Ohm is defined by a graphene quantum Hall resistance standard at NIST. There are some downsides to the quantum Hall resistance standard.

The modern voltage standard is a superconducting integrated circuit known as the Josephson voltage standard; it uses Shapiro steps to relate the absolute size of a set of voltage steps to a frequency standard. Because the voltage standard and resistance standard are independently fixed to physical phenomena, current standards are necessarily defined by the relationship between these two different standards. Unfortunately, the superconducting integrated circuits used as Josephson voltage standards must be operated in very low ambient magnetic field, because large magnetic fields destroy superconductivity. This makes them incompatible with the graphene quantum Hall resistance standard, which must operate in large magnetic fields, generally B > 5T. This is a surmountable problem- in practice it is handled by storing the two standards in different cryostats, or with significant magnetic shielding between them- but the significant distance separating the standards reduces the precision with which the current standard can be defined with respect to our current resistance and voltage standards. One possible way to resolve this conflict is to replace the quantum Hall resistance standard with a Chern magnet resistance standard. Chern magnets show quantized anomalous Hall effects at low or zero magnetic field, meaning they can be installed in very close proximity to Josephson voltage standards in calibration cryostats. Unfortunately, doped topological insulators have such small band gaps that even at the base temperatures of dilution fridges, vertical vegetable tower there is enough thermal activation of electrons into the bulk to limit the precision of quantization of the quantized anomalous Hall effect in these systems. This made the class of Chern magnets discovered in 2013 unsuitable as replacements for the graphene quantum Hall resistance standard. Since intrinsic Chern magnets have now been discovered, and are observed to have band gaps considerably exceeding those of doped topological insulators, it might make sense to replace the graphene quantum Hall resistance standard with an intrinsic Chern magnet resistance standard. The ease of replication of the fabrication process of MoTe2/WSe2 makes that material particularly intriguing as a candidate material for a new resistance standard, but over the past few years new intrinsic Chern magnets have been discovered almost every year, so we may soon be discussing much better materials for this application. In any case, it seems possible and perhaps even likely that Chern magnets will supplant quantum Hall systems as resistance standards in the near future.Of course, that fact didn’t take away the many advantages of magnetic memories, and magnetic memories still persist in a variety of niche applications that depend particularly strongly on one of these advantages. Many computers destined to spend their lives in space still use hard drives, and sensors designed to operate over a wide range of temperatures and with intermittent access to power often use non-volatile magnetic memories as well. This has led researchers to search for phenomena and device architectures that allow magnetic order to be switched either with electrical currents or electrostatic gates.

Until recently, the best technology available capable of electronic switching of magnetism used spin-orbit torques. In a spin-orbit torque device, current through a system with a strong spin Hall effect pumps spin into a separate magnet, which is eventually inverted by the torque exerted by those spins. This technology has matured considerably over the past few years, producing a cascade of new records for low current density magnetic switching and even a few consumer products in the memory market. The discovery of the first intrinsic Chern magnets produced a fascinating surprise for this field. The exotic orbital magnet in twisted bilayer graphene was found to be switchable with extremely small pulses of current, and the resulting current-switchable magnetic bits displaced previously realized spin-orbit torque devices as the ultimate limit in low-current control of magnetism. A flurry of theoretical investigation of these systems followed, dedicated primarily to identifying and generalizing the mechanism underlying current control of magnetism in these systems. A few years later, AB-MoTe2/WSe2 joined twisted bilayer graphene, with a similarly small magnetic switching current. In the intervening time, a new phenomenon had been observed- switching of a Chern magnet with an electrostatic gate, in twisted monolayer/bilayer graphene. All of these phenomena represent newly discovered and now more or less well understood mechanisms for controlling magnetic bits electronically, and by the performance metrics used in the literature they reign supreme. Several electronic switching phenomena known in intrinsic Chern magnets are summarized in Fig. 8.3. Chern magnets differ from the magnetic materials used in more traditional magnetic memories in a wide variety of intriguing ways other than their electronic switch ability. Chern magnets are not metals and thus don’t have the same limitations as metallic magnetic memories. For example, the resistance of a Chern magnet is independent of its size, depending only on fundamental physical constants. This makes the resistance of a Chern magnet completely insensitive to miniaturization. Dissipation does occur in Chern magnets, but it occurs only at the contacts to the Chern magnet, so once electrons enter the crystal they can undergo very long range transport completely free of dissipation. Chern magnets are atomically thin in the out-of-plane direction, and of course if they are separated by insulators they can easily be stacked to increase magnetic bit density. Chern magnets are two dimensional materials, and two dimensional materials already have small radiation cross-sections relative to three dimensional crystals like silicon, but the conduction path through a Chern magnet is both one dimensional and topologically protected, so it is overwhelmingly likely that Chern magnet memories would be even more radiation hard than the thin semiconducting films that form the current state of the art. All of these ideas make Chern magnets interesting candidates as substrates for magnetic memories of the distant future. Of course none of these ideas have been implemented in technologies yet, and that is because intrinsic Chern magnets have only been realized at fairly low temperatures . All of the magnetic memory applications we’ve discussed depend critically on the discovery of intrinsic Chern magnets at considerably higher temperatures, and ideally room temperature.

It also depends on very strong in-plane bonds within the material, which must support the large stresses associated with reaching such high aspect ratios; materials with weaker in-plane bonds will rip or crumble. In practice these materials are almost always processed further after they have been mechanically exfoliated, and the preparation process typically begins when they are pressed onto a silicon wafer to facilitate easy handling. Samples prepared in this way are called ‘exfoliated heterostructures.’ It is of course interesting that this process allows us to prepare atomically thin crystals, but another important advantage it provides is a way to produce monocrystalline samples without investing much effort in cleanly crystallizing the material; mechanical separation functions in these materials as a way to separate the domains of polycrystalline materials. Graphene was the first material to be more or less mastered in the context of mechanical exfoliation, but a variety of other van der Waals materials followed, adding substantial diversity to the kinds of material properties that can be integrated into devices composed of exfoliated heterostructures. Monolayer graphene is metallic at all available electron densities and displacement fields, but hexagonal boron nitride, or hBN, is a large bandgap insulator, making it useful as a dielectric in electronic devices. Exfoliatable semiconductors exist as well, hydroponic bucket in the form of a large class of materials known as transition metal dichalcogenides, or TMDs, including WSe2, WS2, WTe2, MoSe2, MoS2, and MoTe2.

Exfoliatable superconductors, magnets, and other exotic phases are all now known, and the preparation and mechanical exfoliation of new classes of van der Waals materials remains an area of active research. Once two dimensional crystals have been placed onto a silicon substrate, they can be picked up and manipulated by soft, sticky plastic stamps under an optical microscope. This allows researchers to prepare entire electronic devices composed only of two dimensional crystals; these are known as ‘stacks.’ These structures have projections onto the silicon surface that are reasonably large, but remain atomically thin- capacitors have been demonstrated with gates a single atom thick, and dielectrics a few atoms thick. Researchers have developed fabrication recipes for executing many of the operations with which an electrical engineer working with silicon integrated circuits would be familiar, including photolithography, etching, and metallization. I think it is important to be clear about what the process of exfoliation is and what it isn’t. It is true that mechanical exfoliation makes it possible to fabricate devices that are smaller than the current state of the art of silicon lithography in the out-of-plane direction. However, these techniques hold few advantages for reducing the planar footprint of electronic devices, so there is no meaningful sense in which they themselves represent an important technological breakthrough in the process of miniaturization of commercial electronic devices. Furthermore, and perhaps more importantly, it has not yet been demonstrated that these techniques can be scaled to produce large numbers of devices, and there are plenty of reasons to believe that this will be uniquely challenging. What they do provide is a convenient way for us to produce two dimensional monocrystalline devices with exceptionally low disorder for which electron density and band structure can be conveniently accessed as independent variables.

That is valuable for furthering our understanding of condensed matter phenomena, independent of whether the fabrication procedures for making these material systems can ever be scaled up enough to be viable for use in technologies. Consider the following procedure: we obtain a pair of identical two dimensional atomic crystals. We slightly rotate one relative to the other, and then place the rotated crystal on top of the other . The resulting pattern brings the top layer atoms in alignment with the bottom layer atoms periodically, but with a lattice constant that is different from and in practice often much larger than the lattice constant of the original two atomic lattices. We call the resulting lattice a ‘moir´e superlattice.’ The idea to do this with two dimensional materials is relatively new, but the notion of a moir´e pattern is much older, and it applies to many situations outside of condensed matter physics. Pairs of incommensurate lattices will always produce moir´e patterns, and there are many situations in daily life in which we are exposed to pairs of incommensurate lattices, like when we look out a window through two slightly misaligned screens, or try to take pictures of televisions or computer screens with our camera phones. Of course these ‘crystals’ differ pretty significantly from the vast majority of crystals with which we have practical experience, so we’ll have to tread carefully while working to understand their properties. To start with, if we attempt to proceed as we normally would- by assigning atomicorbitals to all of the atoms in the unit cell, computing overlap integrals, and then diagonalizing the resulting matrix to extract the hybridized eigenstates of the system- we would immediately run into problems, because the unit cell has far too many atoms for this calculation to be feasible. Some moir´e superlattices that have been studied in experiment have thousands of atoms per unit cell. There exist clever approximations that allow us to sidestep this issue, and these have been developed into very powerful tools over the past few years, but they are mostly beyond the scope of this document. I’d like to instead focus on conclusions we can draw about these systems using much simpler arguments.

The physical arguments justifying the existence of electronic bands apply wherever and whenever an electron is exposed to an electric potential that is periodic, and thus has a set of discrete translation symmetries. For this reason, even though the moir´e superlattice is not an atomic crystal, we can always expect it to support electronic band structure for the same reason that we can always expect atomic crystals to support band structure. Two crystals with identical crystal symmetries will always produce moir´e superlattices with the same crystal symmetry, so we don’t need to worry about putting two triangular lattices together and ending up with something else.Another property we can immediately notice is that the electron density required to fill a moir´e superlattice band is not very large. This can be made clear by simply comparing the original atomic lattice to a moir´e superlattice in real space . Full depletion of a band in an atomic crystal requires removing an electron for every unit cell , and full filling of the band occurs when we have added an electron for every unit cell. We have already discussed how this is not possible for the vast majority of materials using only electrostatic gating, because the resulting charge densities are immense. Full depletion of the moir´e band, on the other hand, requires removing one electron per moir´e unit cell, and the moir´e unit cell contains many atoms . So the difference in charge density between full filling and full depletion of an electronic band in a moir´e superlattice is actually not so great , and indeed this is easily achievable with available technology. Before we go on, I want to make a few of the limitations of this argument clear. There are two things this argument does not necessarily imply: the moir´e bands we produce might not be near the Fermi level of the system at charge neutrality, and the bandwidth of the moir´e superlattice need not be small. In the first case, we won’t be apply to modify the electron density enough to reach the moir´e band, and in the latter, stackable planters we won’t be able to fill the moir´e band’s highest energy levels using our electrostatic gate. We know of examples of real systems with moir´e superlattice bands that fail each of those criteria. But if these moir´e superlattice bands are near charge neutrality, and if their bandwidths are small, then we should be able to easily fill and deplete them with an electrostic gate. A variety of scanning probe microscopy techniques have been developed for examining condensed matter systems. It’s easy to justify why magnetic imaging might be interesting in gate-tuned two dimensional crystals, but magnetic properties of materials form only a small subset of the properties in which we are interested. Scanning tunneling microscopy is capable of probing the atomic-scale topography of a crystal as well as its local density of states, and a variety of scanning probe electrometry techniques exist as well, mostly based on single electron transistors. It’s worth pointing out that if you’re interested specifically in performing a scanning probe microscopy experiment on a dual-gated device, then these techniques both struggle, because the top gate both blocks tunnel current and screens out the electric fields to which a single electron transistor would be sensitive. Magnetic fields have an important advantage over electric fields: most materials have very low magnetic susceptibility, and thus magnetic fields pass unmodified through the vast majority of materials . This means that magnetic imaging is more than just one of many interesting things one can do with a dual-gated device; in these systems, magnetic imaging is a member of a very short list of usable scanning probe microscopy techniques.

The simplest way in which we can use our nanoSQUID magnetometry microscope is as a DC magnetometer, probing the static magnetic field at a particular position in space . There are situations in which this is a valuable tool, and we will look at some DC magnetometry data shortly, but in practice our nanoSQUID sensors often suffer from 1/f noise, spoiling our sensitivity for signals at low or zero frequency. One of the primary advantages of the technique is its sensitivity, and to make the best of the sensor’s sensitivity we must measure magnetic fields at finite frequencies. We have already discussed how we can use electrostatic gates to change the electron density and band structure of two dimensional crystals. We will discuss shortly a variety of gate-tunable phenomena with magnetic signatures that appear in these systems. It follows, of course, that we can modulate the magnetic fields emitted by these electronic phases and phenomena by modulating the voltages applied to the electrostatic gates we use to stabilize these phases. This is illustrated in Fig. 1.15C: an AC voltage is applied to the bottom gate relative to the two dimensional crystal, and the local magnetic field is sampled at the same frequency by the SQUID. We can use this techniqueto extract δV δB at an array of positions above the two dimensional crystal. This technique is very simple and powerful, but it has a few important drawbacks. It can only produce a quantitative measurement of B if the same scan is performed for a large set of gate voltages, so that δV δB can be integrated. Many ferromagnets, for example, can be locked into quantum states that aren’t their ground states using a ferromagnetic hysteresis loop, and rapidly tuning the electron density tends to relax these phases to their ground states. So whenever we are interested in probing metastable magnetic states, we need to be careful about using this measurement method. Of course, we can also modulate the magnetic field through the nanoSQUID by modulating the position of the nanoSQUID. Since the magnetic field varies rapidly in space, we can often expect to get strong signals when we probe δB δx this way . The position of the nanoSQUID is rapidly modulated using a piezoelectric tuning fork pressed against the side of the nanoSQUID sensor; the details of the tuning fork hardware and measurement are discussed further in the appendix. This measurement method allows us to use the nanoSQUID to probe metastable or even non-gate-tunable magnetic phenomena at finite frequency. It has a few drawbacks of its own, though. The nanoSQUID sensors have parasitic sensitivities to local temperature and electric potential , and if these vary in space the resulting signals will contaminate our magnetic field data. As a result, whenever we use this contrast mechanism we must try to extract differences between two different magnetic states if we want quantitatively precise information about the magnetic field. We can also apply an AC current in the plane of the two dimensional crystal. Large currents will emit detectable magnetic fields through the Biot-Savart law, and under those conditions we can use this contrast mechanism to reconstruct the current density through our two dimensional crystal.

Our studies suggest a combination of its transmission dynamics and how they are affected by management issues, such as the quantity of shade and the density of planting, plus a variety of control from above elements represent a source of control, which sometimes fails .Understanding the general structure of ecological communities has long been a central goal of ecology, from Haeckel to us. Empiricists commonly, and probably necessarily, focus on the community of X, which is to say an assemblage of species defined by some set of criteria: the fungal community of Lake Wobegon, the community of gall-forming insects of oak trees, the microbial community of the human gut, the community of four ciliate species, and so on. Theoreticians perhaps feel less constraint. In the present article, we have defined the community as the herbivores of the coffee plant and their associates, in which top-down control is the goal of management . The framing of regulation from above from theoretical ecology translates directly into biological control from agroecology. Indeed, in agroecology regulation from above is elementary, in that the top-down agents are frequently obvious . However, stopping at that level of understanding may obscure more than clarify, stacking pots much as the simple phrase controlled from above may indeed obscure . Precisely how that control is affected may involve many complicated interactions and contingencies, making, we argue, the framing of complex systems a necessary one.

The fungus that attacks the scale is most efficient when the scale is hyper dense at a local level, something that cannot happen unless it is under the protection of a mutualistic ant, which deters the other predator , which, however, is able to take advantage of a spatial pattern that is self-organized through a Turing-like process, and so forth. Indeed, we argue that the understanding we claim to have of this system so far comes from detailed study, both empirical and theoretical, and, most importantly is dramatically enriched through the application of some of the concepts newly developed in the distinct field of complex systems. Almost 10 years ago, some of us published a summary of this overall system , suggesting that understanding it required more than just an identification of who eats whom. This update emphasizes that point. Our narrative in the present article is perhaps a bit heterodox. We study a very complicated system , and we seek to understand it through theoretical ecology. To some, at least in the recent past, this might imply a large-scale computer model or sophisticated data manipulation. Our approach is distinct, recalling the wisdom of Levins’ paper on the strategy of model building. We seek to understand, at a deep level, how this system works, not necessarily for the purpose of predicting its future state. We offer theoretical propositions, many of which are stimulated by mathematical arguments, but we do not seek what postmodern thinkers would have called a “totalizing discourse” with a large-scale model. Rather, we seek to use recent advances in complex systems as a way of stimulating thought, with the mathematical models that go along with them as “educating our intuition,” as Levins urged frequently. The models themselves represent approximate metaphors for this complex reality, all fitting into a hierarchy of understanding , which is mainly qualitative even though originally formulated through mathematical reasoning.Furthermore, our claim that this is a complex reality is meant to imply something deeper than the obvious claim that it is complicated. It is a complex system.

For example, if the only players in the system were Azteca, C. viridis, and A. orbigera, the system wouldn’t be exceptionally complicated , but it would be a complex system, because it would have a clear emergent property . Even adding the phorid would mean two predators and two prey, but the spatial pattern that emerges and the dependence of one system on a second system operative at a completely distinct time scale is an essential structural component of the system as a whole. The emergence would defy understanding if only the separate component parts were studied, which is to say if it were approached from a purely reductionist perspective. If the only players were the ants and the coffee berry borer, but the ants did not exhibit trait-mediated indirect interactions, the system would be complicated but not necessarily complex. This distinction between complicated and complex is important for our narrative. Because it is a complex system, it requires a more holistic approach to understand and manage, and there’s more potential for surprise . A merely complicated system would not have these characteristics. That our model system is coffee is significant in several ways. First, traditional coffee management, with its characteristic shade trees, helps to create landscapes that are friendly to biodiversity conservation . It is a classic high-quality matrix for all sorts of animals and plants. Second, it involves a commodity that is of extremely high value, sometimes the main source of wealth for entire countries. Third, it is the basis of livelihood for millions of small farmers the world over. Fourth, when properly cultivated with shade, it joins other agroforestry systems in the worldwide struggle against climate change. Given all that, understanding the details of its operation would seem worthwhile, and marshaling recent insights from complex systems to anchor that narrative brings one of the classical questions of community ecology into focus as a practical issue. Consequently, besides being of potential importance for ecology, it makes ecology important for some practical aspects of this important crop.

It is, for example, evident from only a qualitative understanding of the control from above system that a key element is the species of ant that nests in the shade trees and that, if those shade trees are eliminated , the whole control structure will be dramatically interrupted. Questions also arise about generality. Does this model system reflect something more general about the structure of control from above, or does it simply reflect interactions of this one particular system? First, most terrestrial systems have a spatial component involved, and framing the spatial component as one in which a subsystem operates to effectively create a spatial pattern in which other subsystems may operate is likely to apply frequently. Indeed, the idea of a predator–prey system generating a Turing pattern may be increasingly appreciated as more research programs interrogate the idea . Second, population dynamics unfolding on this space are likely to be nonlinear, and this nonlinearity will frequently be of the form that critical transitions lead to an alternative equilibrium within hysteretic zones, which may be multiple and constrain the herbivores above which control is being exerted . Third, the idea that multiple herbivores have their own suite of controlling factors is almost certainly true, but the idea that there will be connections, even if weak, with other sub-components of the control from above, is likely to be characteristic. These three generalities encompass the complex systems topics of Turing pattern formation, critical transitions, hysteresis, chaos, basin boundary collisions, trait-mediated indirect interactions, and scale-dependent spatial processes, all of which are exemplified in our model system, and certainly may be embedded in other systems of control from above. The message is not that these particular topics are essential but, rather, that control from above is not the one-dimensional process frequently imagined of a predator guild preying on a prey guild but, instead, a complex community of predators and parasites and diseases that interact with one another in complicated ways to eventually generate a self-organized system that exerts effective control over the herbivory. Much as one might say that the vertebrate circulatory system is responsible for bringing oxygen to each cell in the body, one might similarly simplify and say that natural enemies in the coffee agroecosystem are responsible for the regulation of potential pests. However, it is the heart, the veins, the arteries, exchanges across membranes, strawberry gutter system and so forth that tell the real story of how the delivery of oxygen to our tissues actually happens. It is a complex system, the details of which are certainly of interest to health and healing. Similarly, in our agroecosystem example, the subsystem that creates large-scale pattern sets the stage for a subsystem involving a predator and a disease that affect regulation of one pest, whereas the community structure of ants determines the efficiency of their predacious activities on a second pest and the disease that helps regulate the first pest is an antagonist to the third pest. This is all to say that yes, it is control from above, but that control is delivered through the ecological complexity of the community of natural enemies. It is misleading to suggest that listing the natural enemies and merely identifying them as such is sufficient. It is only through the lens of the reality of its state as a complex system that we may gain full appreciation of the ecological principle of top-down control, which then can be fully exploited in attempts to aid the management of this important agroecosystem. There is something of a conundrum in this narrative.

Although it is clear that knowledge of all the ecological complexity could inform practical decisions that producers might want to make, is such detailed knowledge really necessary to provide useful advice to the farmer? If ecological knowledge of the particular system is primitive, could well meaning agroecological advisors give advice that will have unintended negative consequences? Post-WWII industrial agriculture enthusiasts embraced DDT and other pesticides creating the well-known pesticide treadmill that haunts us still today. Indeed, that is one of the issues that caused many environmentally conscious analysts to call for the science of ecology to be more actively embraced by agricultural planners. However, ecology is complicated. Secondary consequences cannot necessarily be predicted short of detailed study and the normal rules of thumb extrapolated from a few experiments or extralocal traditions could backfire. Perhaps the famous medical practitioner’s oath primum non nocere makes sense in agriculture as well. As farmers seek solutions to perceived problems on their farms, agroecologists rightly wish to use the science of ecology to help. However, frequently , ecological knowledge of the particular system is not very well understood because it is only recently that agroecological advocates have begun to break into the mainstream, and the basic research required to understand some of the vexing problems the farmers face has yet to be done. It is therefore common to use a few rules of thumb: avoid monocultures, don’t poison your natural enemies, maintain healthy soil, and so on. Such rules of thumb, on the basis of perceived ecological rules, for the most part make sense and probably conform well to the admonition primum non nocere. However, it is worth remembering the dust bowl, pest resurgence following pesticides, ocean dead zones, and other consequences that we live with today because a previous generation of farm advocates, equally sincere in their desires to help farmers, were prematurely confident in the ability of their tools to help the farmer.There are a growing number of examples of a positive relationship between diversity and ecosystem service. As an ecosystem service, pollination can increase the fruit or seed quality or quantity of 39 of the world’s 57 major crops, and a more diverse pollinator community has been found to improve pollination service . For some crops, wild bees are more effective pollinators on a per visit basis than honey bees and/or can functionally complement the dominant visitor. A less explored reason is that in diverse communities, interspecific interactions potentially alter behaviour in ways that increase pollination effectiveness. Little is known about how community composition affects pollinator behaviour and the role such species interactions play in determining diversity–ecosystem service relationships. Interspecific interactions can result in non-additive impacts of diversity on ecosystem functions. Examples include the facilitation of resource capture in diverse groups of aquatic arthropods, and non-additive increases in pest suppression and alfalfa production in enclosures with diverse natural enemy guilds. In diverse communities, one mechanism by which species interactions may augment function is the potential to modify the behaviour and the resulting effectiveness of the ecosystem service providers. Interactions with non-Apis bees cause Apis mellifera L. to move more often between rows of sunflower, increasing their pollination efficiency. Such changes in pollinator movement are particularly important in crop species with separate male and female flowers, and those with self-incompatibility .