Pollinator Dependence Research Articles

Vegetative traits, floral biology, and mutualistic interactions in the tropical mountain shrub Ribes ciliatum (Grossulariaceae)

Plant species in tropical mountain ecosystems experience significant environmental variation across short spatial distances. These systems offer an opportunity to assess geographic variation in plant traits in relation to biotic and abiotic environments. We examined plant vegetative and reproductive traits in the shrub R. ciliatum across two native conifer forests in central Mexico. We measured plant height, number of branches, leaf size, flower production, floral morphology, floral longevity, and plant reproductive success in R. ciliatum populations found in fir forests (3100 m) and Hartweg's pine forests (subalpine habitat, 3700 m). We also quantified the level of pollinator dependence, pollinator visitation rates, and fruit consumption rates by frugivorous birds in both populations. Plants were shorter and had smaller leaves in the subalpine forest than in the fir forest. Floral longevity decreased in the subalpine forest, but flower production, flower size, and fruit weight remained similar across populations. Fruit set and pollinator visitation rates were higher in the subalpine forest; however, seed weight and fruit consumption rates did not differ between sites. Hummingbirds and bumblebees were the primary pollinators of R. ciliatum, and the bird Ptiliogonys cinereus was the most important fruit consumer at both sites. Fruit set was entirely dependent on pollinators. Reduced plant size in the subalpine forest coincides with a general pattern associated with high mountain environments. In contrast, reproductive characters had a closer relationship to the pollination environment. The absence of variation in flower size and shape was consistent with the similarity in the composition of the pollinator community. Meanwhile, compared to lower-elevation forests, the subalpine forest exhibited shorter-lived flowers and increased fruit set, associated with higher pollinator visitation rates. Ribes ciliatum is a key resource for pollinators and frugivores at a time of year when few other floral resources are available in these high-elevation mountain forests.

How pollinator dependence may mediate farmer adoption of pollinator supporting practices and perceptions: a case study from western France

There is limited knowledge on why farmers adopt pollinator-supporting practices, which is crucial to stimulate their adoption. The dependence of farmers on pollination may influence their perception of pollinators and their willingness to adopt these practices. We addressed why farmers adopt pollinator-supporting practices using a 2011 survey conducted within a cereal plain in western France, where farmers were moderately dependent on pollination for crops like oilseed rape and sunflower. We assessed the factors influencing the adoption of practices to promote pollination, including pollination dependence. We found no effect for pollination dependence. Conversely, we found that farm size, pesticide use, advisory services and the perception of costs decreased the willingness to adopt, while older farmers were more incline to adopt. We also evaluated perceptions related to pollinators: more than 85% of farmers considered bees important for crop production and recognized pesticides as a major cause of decline. We found no effect of pollination dependence on farmers’ perceptions. Compared to similar studies over the past decade, we found similarities, particularly regarding pollinator-related perceptions. Finally, we compared the willingness to adopt in 2011 with the actual adoption in 2024, showing that there has been little change. This raises questions on the pathways to promote the adoption of pollinator-supporting practices to ensure for the future of pollinator conservation.

Pollinator effectiveness and pollination dependency of bilberry (Vaccinium myrtillus) in Swedish hemi-boreal forests

Intensification of forest management to increase production of biomass has resulted in considerable habitat degradation with negative impacts on insect biodiversity, including beneficial insect groups such as pollinators. Yet, little is known about how reliant forest understory plants, such as bilberry (Vaccinium myrtillus), are on insect pollinators for reproduction. Here, we quantified the structure of the bilberry flower visitor community, compared the pollination effectiveness of the most common pollinators, and experimentally quantified bilberry pollination dependency. The bilberry pollinator community was comprised of several bee and hoverfly taxa. Bumblebees were the most important pollinators due to their high abundance and pollination effectiveness. Other bees, in particular, Andrena spp., and to a smaller extent, hoverflies, were also effective pollinators. Furthermore, bilberry was strongly pollen-limited, with only 40% of open-pollinated flowers setting fruit. Bilberry supports a diverse flower visitor community within hemi-boreal forests, for which it is highly dependent for reproduction. Given the ecological and cultural value of bilberry, the importance of insect pollinators for understory plants should be considered within forest management strategies.

Animal‐pollinated crops and cultivars—A quantitative assessment of pollinator dependence values and evaluation of methodological approaches

Abstract Crop pollinator dependence (PD) values are key when assessing a pollinator's contribution to agriculture, guiding management plans and policies for sustainable crop production. However, the available global compilations of crops PD are outdated and neglect variability between related crops and accessions (variety/cultivar), as well as pollen limitation (PL), that is the production lost due to inadequate pollen receipt. Here, we obtained quantitative PD values for animal‐pollinated crops and their accessions, using data from available pollination experiments worldwide. We also tested pollination methodologies to assess their impact on PD values and to define suitable methodological guidelines for future pollination studies. We provide a list of continuous PD values for 141 crops, including 317 accessions and 37 crops not listed in previous assessments. We found that, globally, 74% of animal‐pollinated crops are highly dependent on pollinators, and more than 40% of their production is associated with animal pollination. Pollen limitation was detected in 51% of the dataset entries, indicating that estimates calculated with open pollination studies underestimate crop pollinator dependence and, therefore, do not represent the true contribution of pollinators to food production. Synthesis and applications: Commonly applied methods for assessing PD values can lead to underestimations. Future studies evaluating pollinator dependence levels of crops and their accessions (i.e. potential pollinator contribution) should consider the possibility of pollen limitation in the study site, incorporating hand pollen supplementation (to open flower), open pollination, and pollinator exclusion treatments, preferably using the whole plant or branch as the unit of assessment. The PD values provided here, from studies that allow the incorporation of the concept of pollen limitation, enable more accurate quantifications of pollinator contribution to crop production. These PD values are an invaluable baseline and a requirement for future accurate evaluations of the value of pollinators for food security, supporting pollinator‐friendly practices in agroecosystems.

Pollinator dependence and pollination deficit in Hedera helix, and effects on frugivore feeding choices

English ivy (Hedera helix) is an important resource for wildlife in rural and urban ecosystems. It provides pollen and nectar for flower-visiting insects during autumn and fruits for frugivores during winter and spring. A requirement of insect pollination for fruit set in ivy implies that recent declines in pollinator populations can threaten food supply for frugivores. This study investigated the link between pollination services and the quantity and quality of fruit produced in ivy, and how that could in turn influence frugivore feeding choices, in a mixed woodland and an urban garden habitat respectively. Surveys on pollinator community and activity were conducted to assess the overall level of pollination. A set of experiments involving insect exclusion, open pollination, and extra pollen supplementation was performed to reveal the level of pollinator dependence and pollination deficit in ivy. Additionally, the removal of these fruits by frugivores was measured to test whether frugivore feeding preferences are influenced by the initial level of pollination. Our results showed that the quantity and quality (size) of fruit produced in ivy were significantly reduced under insect exclusion, which is strong evidence for pollinator dependence. Pollination deficit was also identified at both sites. Furthermore, the data indicate that frugivores can display some degree of preference for well-pollinated ivy fruits. Taken together, our study shows that declines in pollination services will have direct impacts on the availability and quality of ivy fruits for frugivores. Maintaining the health of pollinator communities in both urban and rural habitats could therefore ensure healthy ecosystem functioning.

Pollination services to crops of watermelon (Citrullus lanatus) and green tomato (Physalis ixocarpa) in the coastal region of Jalisco, Mexico.

Bees play a pivotal role as pollinators in crops essential for human consumption. However, the global decline in bee populations poses a significant threat to pollination services and food security worldwide. The loss and degradation of habitats due to land use change are primary factors contributing to bee declines, particularly in tropical forests facing high deforestation rates. Here, we evaluate the pollination services provided to crops of watermelon (Citrullus lanatus) and green tomato (Physalis ixocarpa) in three municipalities in the state of Jalisco, Mexico, a place with Tropical Dry Forest, during years 2008, and 2014 to 2017. Both crops are cultivated in the dry season, approximately during the months of November to March. We describe the composition of the pollinator community and their visitation frequency (measured through the number of visits per flower per hour), and we assess the impact of pollinators on plant reproductive success and the level of pollinator dependence for each crop species (measured through the number of flowers that developed into fruits). We also evaluate how the landscape configuration (through the percentage of forest cover and distance to the forest) influences richness and abundance of pollinators (measured as number of species and individuals of pollinators per line of 50 m), and we use the model Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) to map and value the pollination service in both crops. InVEST Crop pollination model is a simulation focuses on wild pollinators providing the pollinator ecosystem service. Our findings indicate that Apis mellifera was the primary pollinator of both crops, one of the few abundant pollinators in the study region during the dry season. In experiments where pollinators were excluded from flowers, watermelon yielded no fruits, while green tomato experienced a 65% reduction in production. In the case of green tomato, fruit set showed a positive correlation with pollinator abundance. A positive association between forest cover and total pollinator abundance was observed in green tomato in 2008, but not in watermelon. Additionally, a positive relationship was observed between the abundance of bees predicted by the InVEST model and the abundance of bees observed in green tomato flowers in 2008. In the study region, green tomato and watermelon rely on pollinators for fruit production, with honeybees (from feral and managed colonies) acting as the primary provider of pollination services for these crops. Consequently, the conservation of natural areas is crucial to provide food and nesting resources for pollinators. By doing so, we can ensure the diversity and abundance of pollinators, which in turn will help secure food security. The findings of this study underscore the critical need for the conservation of natural areas to support pollinator populations. Policymakers should prioritize the protection and restoration of habitats, particularly tropical forests, which are essential for maintaining the diversity and abundance of pollinators.

Food plants in Brazil: origin, economic value of pollination and pollinator shortage risk

Pollination is a key ecosystem service of critical importance for food production. However, globally, several regions are already experiencing pollinator shortage as pollinators are declining. Here, we investigate the origin, pollinator dependence and economic value of 199 food crops cultivated in Brazil to understand to which extent (1) Brazilian agriculture is vulnerable to pollinator shortage, and (2) Brazilian society has already achieved a comprehensive perspective about crop dependence. We used Brazil as a case study as it is a megadiverse tropical country and the 3rd largest world crop producer and exporter, with most of the crops depending on pollinators. Our findings revealed that over half (53.7%) of the food crops in Brazil are native, with the North region of Brazil housing the higher diversity of native crops, in contrast with the South and Southeast regions. Additionally, considering the reproductive systems, among native food crops, 65.6% exhibit self-incompatibility or dioecy (i.e., requiring obligatory cross-pollination), whereas 30.6% of exotic food crops display this trait. Overall, Brazilian municipalities produce more exotic crops than native ones, with almost 4/5 of the total agricultural area of the country dedicated to the cultivation of exotic crops, which are generally self-compatible commodities that rely low to modestly on pollinators. Regarding the biomes, we observe that this pattern is followed by most of them, but for the Caatinga dry forest, where native crops dependent on pollinators predominate. However, when soybean is removed from the analysis, the areas devoted to exotic crops always decreased, even being equal to native crops in the Atlantic forest. Our results also indicate that considering the pollinator shortage, some Brazilian biomes may be at risk of losing >20% of their yields, mainly in the Caatinga dry forest and the Atlantic forest. Therefore, in this paper, we are discussing that the expansion of monocultures in Brazil's agricultural lands may have several impacts on the provision of pollination services, food production and, then, on food security not only for the Brazilian population, as Brazil is the 3rd largest world agricultural producer and exporter.

Effects of a field-sprayed antibiotic on bee foraging behavior and pollination in pear orchards

Broadcast spraying of antibiotics in crops is widely used for controlling bacterial plant pathogens. The effects of antibiotics on non-target (and especially beneficial) organisms in cropping systems, however, are not well studied. Pollinators are of particular concern because in pear and apple crops, antibiotics for controlling fire blight (Erwinia amylovora) are sprayed during bloom, likely exposing pollinators. This is especially relevant as laboratory evidence suggests that antibiotics could have sublethal effects on bee foraging behavior and colony health. But to our knowledge these potential impacts have not been studied in field settings. Here, we compared the effects of two fire blight control methods, a single spray of an antibiotic (oxytetracycline) and a biological antagonist (Aureobasidium pullulans), on honey bee (Apis mellifera) foraging, pollination, and fruit set in pear orchards. Complementing these field assessments, we conducted laboratory experiments to examine the effects of these treatments on locomotion and foraging behavior of a bumble bee species, Bombus vosnesenskii. We found that honey bees visited fewer flowers and foraged longer on each flower in orchards sprayed with antibiotics than with a biological product, but there were no differences in crop pollination and seed set. The pear cultivars we worked in, however, can self-pollinate. In the lab, we found that feeding on high doses of either the antibiotic or the biological antagonist reduced bumble bee foraging relative to controls. The limited impact of antibiotics on pear pollination observed in this study suggest that antibiotics pose a low economic risk to pear growers, especially for self-compatible cultivars. Still, crops with higher pollinator dependence may be affected by reductions in bee visitation. Future studies should examine the impacts of multiple antibiotic sprays within a season, which are common during warm springs, and their long-term health impacts on both individual bees and colonies.

Evolutionary history and climate co‐determine the geographical variation in pollination modes of angiosperms in China

AbstractAimPollination is an essential stage of angiosperm reproduction, and the mode of pollination plays a major role in driving evolutionary and ecological responses of plants to environmental changes. However, the effects of climate, evolutionary history and floral traits (i.e. plant sexual systems) on pollination mode variation remain unclear. Here, we explored the biogeographic patterns in pollination mode frequency and tested the hypothesis that insect pollination prevails in warm humid regions with old floras due to high pollinator dependence, whereas wind pollination is more frequent in arid regions with younger floras and is more strongly associated with dioecy.LocationChina.Time periodSince the Last Glacial Maximum.Major taxa studiedAngiosperms.MethodsUsing data on pollination modes and geographic ranges of 29,719 angiosperm species in China, we mapped the biogeographic pattern of pollination mode frequency. Phylogenetic logistic regressions and generalized linear mixed models were employed to evaluate the relative importance of climate, evolutionary history (represented by phylogenetic conservatism and grid‐level mean genus age) and sexual systems on variations in pollination modes across species and space.ResultsEvolutionary history was the strongest correlate of pollination mode variation across species and space. The proportion of insect‐pollinated species was higher in humid regions with old floras, but lower in arid regions with young floras. Evolutionary history and temperature dominated variations in pollination mode frequency in humid areas, while precipitation dominated in arid areas. Climate influenced geographic pattern in pollination mode frequency both directly and indirectly via its effects on species richness and plant sexual systems.Main ConclusionsOur results showed that geographic pattern in angiosperm pollination mode frequency is dominated by evolutionary history followed by climate, which extended previous findings of climate‐driven mechanisms. Our findings demonstrate the importance to incorporate evolutionary history in understanding the mechanisms underlying the functional biogeography of plant traits.

Pollinator-dependent crops significantly contribute to diets and reduce household nutrient deficiencies in sub-Saharan Africa

Recent literature highlights the potential of animal pollinator-dependent (PD) crops in enhancing food and nutrition security, although there is a lack of detailed household-level estimates. In this study, we investigate the nutrient composition, productivity, and contribution of PD and pollinator-independent (PI) crops to household nutrition in four sub-Saharan African (SSA) countries. We also evaluate the impact of reallocating resources from PI crops to PD crops on nutrient deficiencies, utilizing nationally representative panel data from three waves and over 30,000 household-year observations. Our findings reveal that PD crops exhibit higher micronutrient content per unit, albeit with lower macronutrient content compared to PI crops. PI crops have higher yield of calories per hectare while PD crops have higher vitamin A yield per hectare. However, protein and iron yield for PD and PI crops varies across countries. PI crops predominantly contribute to macronutrients and iron, while PD crops significantly contribute to vitamin A production. Our econometric results demonstrate that increasing the cultivation of PD crops relative to PI crops reduces the prevalence of nutrient deficiencies and increases crop income without compromising macronutrients production. This suggests that greater investment in PD crop production can be an integral approach to achieving nutrition security in SSA.

Compatibility systems and pollinator dependency in morning glory species (Convolvulaceae)

BackgroundThe Convolvulaceae is a large family containing species exhibiting a range of breeding systems and pollinated by diverse animal taxa. We studied the pollination ecology of 15 Convolvulaceae species, representing seven genera (Argyreia Lour., Camonea Raf., Evolvulus L., Hewittia Wight & Arn., Ipomoea L., Merremia Dennst. ex Endl., and Operculina Silva Manso), in northeastern Thailand, a family that is highly diverse yet understudied in the paleotropics. Specifically, we studied their compatibility systems and degrees of pollinator dependency using pollination experiments, examined pollinator composition and visitation rates using video observation, and determined if there is an association between pollinator visitation rates and degree of pollinator dependence.ResultsOur results showed that most species are self-compatible, but the degree of pollinator dependence varies. Six species were found to be highly dependent on pollinators, as two are self-incompatible and four are self-compatible but had reduced seed set when pollinators were excluded, possibly due to herkogamy. Seven species showed low dependence on pollinators and seed set remained high when pollinators were excluded. Pollinator dependence was inconclusive for two species as seed set was low in all pollination treatments. We also found an association between pollinator visitation rates and degree of pollinator dependence. Specifically, species exhibiting high pollinator dependence received frequent visits from pollinators, while species exhibiting low pollinator dependence either received frequent visits from pollinators (and received high amounts of xenogamous pollen) or infrequent visits from pollinators (and received significantly lower amounts of xenogamous pollen). Most of our study species were primarily visited by bees (e.g., Lasioglossum, Amegilla, Apis, and meliponines), with the exception of one night-blooming species that was visited primarily by crepuscular butterflies and hawkmoths.ConclusionsThe cumulative findings of this study demonstrate how pollinator dependence is influenced by breeding system, and suggest that pollinator visitation is consistently high for species exhibiting high pollinator dependence but varies across species exhibiting low pollinator dependence. Our findings are also important for assessing the conservation risks of paleotropical Convolvulaceae.

Being a tree crop increases the odds of experiencing yield declines irrespective of pollinator dependence

Being a tree crop increases the odds of experiencing yield declines irrespective of pollinator dependence

Beyond pollen:ovule ratios: Evolutionary consequences of pollinator dependence and pollination efficiency for pollen and ovule production in angiosperms.

The relative per-flower production of ovules and pollen varies broadly with angiosperm mating systems, with outcrossing types commonly producing more pollen grains per ovule than selfing types. The evolutionary causes of this variation are contentious, especially the relevance of pollination risk. Resolution of this debate may have been hampered by its focus on pollen:ovule (P:O) ratios rather than on the evolution of pollen and ovule numbers per se. Using published mean ovule and pollen counts, we analyzed associations with the proportion of removed pollen that reaches stigmas (pollen-transfer efficiency) and differences between pollinator-dependent and autogamous forms within and among species. Analyses involved Bayesian methods that simultaneously considered variation in pollen and ovule numbers and accounted for phylogenetic relatedness. We also assessed the utility of P:O ratios as mating-system proxies and their association with female outcrossing rates. Median pollen number declined consistently with pollen-transfer efficiency among species, whereas median ovule number did not. Similarly, in both intraspecific and interspecific analyses, pollinator-dependent plants produced more pollen than autogamous plants, whereas ovule production did not differ statistically. Distributions of P:O ratios overlapped extensively for self-incompatible and self-compatible species and for different mating-system classes, and P:O ratios correlated weakly with outcrossing rate. Our findings demonstrate that pollinator dependence and pollination efficiency commonly influence the evolution of pollen number per flower but have more limited effects on ovule number. P:O ratios provide ambiguous, possibly misleading, information about mating systems, especially when compared among clades.

Pollen limitation and context‐dependent alleviating mechanisms in a co‐flowering alpine grassland community

The consequences of community metrics (e.g. co‐flowering diversity and floral density) and plant traits (e.g. pollinator dependency and trait similarity) on pollen limitation (PL) may depend on pollinator‐mediated competitive or facilitative interactions among plants in co‐flowering communities, which could vary with community contexts (i.e. different altitude communities) and under human disturbances (e.g. livestock grazing). However, the mechanisms to alleviate PL under different contexts, considering pollinator‐mediated interactions among neighboring plants are unclear. We investigated PL under grazing versus ungrazing conditions in low versus high altitude alpine meadows on the Tibetan Plateau to uncover the underlying mechanisms mediating PL associated with livestock grazing. We found that PL is prevalent in alpine grasslands, irrespective of community contexts. Grazing exclusion decreased PL in the two sites but in different ways. At the high‐altitude site, PL was reduced by the exclusion of grazers through increased trait similarity (suggesting facilitation). While PL was reduced by decreased trait similarity (suggesting competition avoidance) under grazing exclusion at the low‐altitude site. Our results provide a mechanistic understanding of PL in co‐flowering alpine grassland communities under distinct human disturbances at different altitudes, emphasizing the role of pollinator‐mediated interactions among plants on plant reproductive success.

The importance of multi-year studies and commercial yield metrics in measuring pollinator dependence ratios: A case study in UK raspberries Rubus idaeus L.

The benefit of pollinators to crop production is normally calculated using "pollinator dependence ratios," which reflect the proportion of yield lost (here reported as a value between 0 and 1) in the absence of pollinators; these ratios are quantified experimentally using pollinator exclusion experiments. Pollinator dependence ratio estimates can vary considerably for a single crop, creating large, frequently overlooked, uncertainty in economic valuations of pollinators. The source of this variation is usually unclear. We experimentally measured the pollinator dependence ratio of two UK commercial cultivars of raspberry Rubus idaeus L., using a range of yield metrics-fruit set, marketable fruit set, fruit weight, and marketable fruit weight-over 3 years (2019-2021), to quantify the effects of yield metric, interannual variation, and cultivar on pollinator dependence ratio estimates. We found a difference in the pollinator dependence ratio for fruit set of 0.71 between 2019 and 2020, showing the importance of carrying out exclusion studies over multiple years. Averaged over multiple years and two cultivars, the dependence ratio was 0.68 measured using marketable fruit set and 0.64 using marketable fruit weight. Imposing a quality threshold (size and shape) below which fruits would not be of commercial value (marketable fruit set/weight) dramatically increased both the pollinator dependence ratio and subsequent economic valuations of pollination service derived from it. Our study shows that, for raspberry, estimates of the pollinator dependence ratio, and therefore, the economic value of insect pollinators, are highly sensitive to the choice of yield metric and can change between years and cultivars. Many economic decisions about pollinator management, at farm, regional and national scales rely on estimates of pollinator dependence. We, therefore, recommend that for estimating pollinator dependence ratios, pollinator exclusion studies are conducted over three or more years and use yield metrics that incorporate quality criteria linked to actual market values and commercial thresholds.

Does pollinator dependence decrease along elevational gradients?

Plants have long been thought to be less dependent on pollinators for seed production at higher elevations due to adverse pollination environments. However, recent research has yet to consistently support the generality of this expectation. In this study, we asked whether pollinator dependence decreases along an elevational gradient and how it varies with various reproductive traits. To answer these questions, we quantified pollinator–plant associations and various reproductive traits for 112 flowering plants spanning a large elevational gradient (990–4260 m a.s.l.) in the Qinghai-Tibet Plateau. We found that flowering plants in the Qinghai-Tibet Plateau region are highly dependent on pollinators for seed production (76.2% of seed production was contributed by animal pollinators and 44.6% of plants would produce no seed without pollinator visitation). Contrary to our expectation, there was no significant elevational gradient in pollinator dependence index. Although the pollinator dependence index was not significantly correlated with pollen limitation, flower size, floral longevity, or reward type, it was correlated with compatibility status and flowering time. These findings indicate that pollinator dependence does not decrease along an elevational gradient in the Qinghai-Tibet Plateau. Our study also highlights the severe vulnerability of flowering plant seed production to pollinator declines under global change in the Qinghai-Tibet Plateau region, particularly for early-flowering or self-incompatible plants growing at higher elevations (e.g., subnival belt).

Economic assessment of entomophilous pollination in crops from Argentina: possible effects of the pollinator crisis in agriculture

In Argentina, food production is the basis of economic and social development. Several crops depend on entomophilous pollination. However, wild and managed pollinators are threatened by conventional agricultural management practices. In this work, we evaluate the economic value attributed to entomophilous pollination (EEV) of the main crops between 2013 and 2018. Our study focused on analyses of crops with varying degrees of pollinator dependence in terms, their harvested area, yield and total economic value (EV). The EEV attributed to pollinators and the vulnerability of each crop category were estimated. The EEV attributed exclusively to entomophilous pollination, in the 27 crops analyzed, was US$ 4.437 million, representing a contribution of the pollinators of 21,83% of the EV and 13,8 million tons of agricultural products. The EEV in decreasing order is industrial crops, fruit trees, vegetables, nuts and citrus. In industrial crops, where managed pollinators are not used, the contribution of pollinators was high, reaching US$3.655 million. Fruit trees and vegetables are the most vulnerable to an eventual decrease or absence of pollinators with estimated vulnerability rates of 68 and 38% respectively. These results show the economic contribution of the pollinators to the country's agriculture, the high vulnerability of agroecosystems and the effects in quantitative terms of a potential reduction in food production due to a pollination deficit. Finally, this work may be useful to guide decision-making and establish public policies aimed at promoting diversification and sustainability of agricultural models to guarantee food security.

Soybean dependence on biotic pollination decreases with latitude

Identifying large-scale patterns of variation in pollinator dependence (PD) in crops is important from both basic and applied perspectives. Evidence from wild plants indicates that this variation can be structured latitudinally. Individuals from populations at high latitudes may be more selfed and less dependent on pollinators due to higher environmental instability and overall lower temperatures, environmental conditions that may affect pollinator availability. However, whether this pattern is similarly present in crops remains unknown. Soybean (Glycine max), one of the most important crops globally, is partially self-pollinated and autogamous, exhibiting large variation in the extent of PD (from a 0 to ∼50% decrease in yield in the absence of animal pollination). We examined latitudinal variation in soybean’s PD using data from 28 independent studies distributed along a wide latitudinal gradient (4–43 degrees). We estimated PD by comparing yields between open-pollinated and pollinator-excluded plants. In the absence of pollinators, soybean yield was found to decrease by an average of ∼30%. However, PD decreases abruptly at high latitudes, suggesting a relative increase in autogamous seed production. Pollinator supplementation does not seem to increase seed production at any latitude. We propose that latitudinal variation in PD in soybean may be driven by temperature and photoperiod affecting the expression of cleistogamy and androsterility. Therefore, an adaptive mating response to an unpredictable pollinator environment apparently common in wild plants can also be imprinted in highly domesticated and genetically-modified crops.

The iconic cactus of the Caatinga dry forest, Cereus jamacaru (Cactaceae) has high sphingophily specialization and pollinator dependence.

Cereus jamacaru is a cactus distributed in Northeastern Brazil, with high symbolic value to this region. However, the interaction, behavior and the role of pollinators remains poorly understood. Here, we investigate the reproductive biology, addressing the ecological significance of floral attributes, including details about floral signaling. The study was carried at three areas of the Caatinga, in 2015, 2017 and 2021. We analyzed the floral morphometry, volume and concentration of the nectar, and characterized the colour and scent of flowers. Additionally, we described the pollinator behavior and performed controlled pollination experiments. The 'Mandacaru' is self-incompatible, has nocturnal anthesis and the nectar is accumulated as droplets in a long hypanthial tube. The flowers have a reflective pattern with a dark outer surface and a white inner surface. (E)-nerolidol is the major component (87.4%) of its floral perfume. We registered the sphingid moth Cocytius antaeus visiting the flowers. The floral attributes, attractants and rewards drives to a sphingophily, and the pollination treatments showed the dependence to fruit set by C. antaeus, the pollinator registered. In this case, if the apparent lack of pollinator diversity encompasses its entire range, the loss of the hawkmoth could severely impact the reproductive success of the cactus.

Animal pollination dependence in Feijoa [Acca sellowiana (Berg) Burret] (Myrtaceae) and variation of pollinators between regions of Uruguay

The Feijoa “Guayabo del país” (Acca sellowiana) is a native Myrtaceae whose fruits have a great commercial potential for their nutritive properties. The objectives of this study were to determine the extent to which fruit production depends on biotic pollination and to identify potential pollinators in Uruguay. Two farms and three park, located in Salto and Canelones were used for the study. The percentage of fruit set in the branches excluding pollinators did not exceed 5.1%, whereas in the branches with free access of pollinators it varied between 10.4% (Salto) and 90.9% (park trees, Canelones). A total of 28 insect species and 3 Passeriforme species were identified on the flower varying with the region. Apis mellifera were present on all plantations with high frequency. Remarkably, 7 species of native bees and 3 species of native passerines were found only in the southern trees of the country. Some pollinators can be managed to improve production, of commercial quality, like honeybees or bumblebees.