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Interspecific crop diversity (e.g., intercropping) has been documented to promote sustainability in agroecological systems with benefits for pollination services and insect pollinators. These benefits may also be extended to intraspecific crop diversity (e.g., cultivation of multiple genotypes or cultivars in a production space), but no review to date has examined the benefits of intraspecific crop diversity for pollination and pollinator communities. While mixing cultivars is necessary and a widespread practice for pollination of self-incompatible or male-sterile crops, it is not as widespread for other crop species. However, many other crops have shown reduced yield quantity or quality with self-fertilization due to partial self-sterility, early acting inbreeding depression, and xenia. These crops could thus experience increased production in diverse cultivar mixtures. Cultivar mixtures could also benefit pollinator communities through providing complementary and temporally consistent floral resources, with cascading effects on pollination services. However, successfully implementing cultivar mixtures requires an understanding of how cultivar identity and arrangement affect successful cross-pollination. In this review, we describe the potential benefits of increased intraspecific crop diversity for optimal pollination and pollinator populations across insect-pollinated crops. Additionally, we explore how research advances in cultivar characteristics and insect pollinator behavior and movement, as well as crop pollen flow, can inform cultivar mixtures and spatial arrangements. We find evidence that mixing cultivars, even in self-compatible crops, improves pollination outcomes and yields. Additionally, given insect pollinator behavior and pollen flow, such mixing must occur at relatively small spatial scales. Furthermore, cultivar diversity could ensure successful pollination and resource production for pollinators under extreme weather events. We also discuss costs and benefits of diverse cultivar mixtures from a grower’s perspective and offer suggestions for future research including translating findings within the context of farming systems so that recommendations are practical and achievable. [ABSTRACT FROM AUTHOR]

Resource competition between wild pollinators and managed honeybees (Apis mellifera) has the potential to detrimentally impact insect biodiversity as well as wild plant and crop pollination. As honeybees are central place foragers, their competitive impact on wild bees is expected to be structured by hive proximity, in conjunction with foraging decisions related to landscape‐level resource availability. Yet, how these factors structure dietary niche overlap between wild bees and managed honeybees remains unclear. We conducted a field experiment in seminatural grasslands, where honeybee foraging densities and niche overlap with buff‐tailed bumblebees (Bombus terrestris) were measured at four distances (<100, 500, 1000 and 2000 m) from experimentally placed apiaries, during and after the blooming period of mass‐flowering oilseed rape (Brassica napus). We measured honeybee foraging densities using standardized transect surveys, and quantified species diet composition and dietary niche overlap from pollen samples collected from both bee species. Honeybee foraging densities were highest near apiaries and declined sharply beyond 500 m from the apiaries. However, niche overlap was unrelated to hive proximity but positively related to the availability of oilseed rape. Furthermore, there were significant inter‐ and intraspecific differences in pollen diet composition and breadth throughout the season. Synthesis and applications: Niche overlap between honeybees and bumblebees in agricultural environments was due to resource sharing of mass‐flowering oilseed rape. When both honeybees and bumblebees predominantly forage on wild plants, they maintain distinct pollen diets, suggesting there is a low risk of resource competition between these generalist taxa. Conservation actions that promote floral resource availability and diversity in agricultural landscapes are crucial to maintain niche differentiation between managed honeybees and wild bees. [ABSTRACT FROM AUTHOR]

Global demand for vegetable oil is projected to expand to 28 Mt by 2028. Oilseed rape (OSR) is the predominant oilseed crop in Europe. Its nutritional value is determined by seed oil content and fatty acids (FAs) composition. Insect pollination increases seed oil content, however, its benefit on FAs composition remains unknown. In this study, we address this gap by investigating the variation of OSR seed oil content and FAs composition along a gradient of bee abundance in farmed OSR fields. We used a pollinator exclusion experiment to disentangle the contribution of pollination processes, i.e. wind, self and insect pollination. We show that bees improved OSR nutritional value by increasing amount of poly-unsaturated FAs and decreasing the amount saturated and trans-saturated FAs. In addition, oil content was higher in seeds with than without access to pollinators. Our study provides for the first time, to the best of our knowledge, evidence that insect pollination enhances the quality value of OSR oil by affecting FAs composition. Such effect implies potential negative consequences with any further decline of pollinator abundance. More investigations are also needed to better understand the mechanisms by which insect pollination affects FAs composition, and the way to enhance such mechanisms.

Extreme heat poses a major threat to plants and pollinators, yet the indirect consequences of heat stress are not well understood, particularly for native solitary bees. To determine how brief exposure of extreme heat to flowering plants affects bee behaviour, fecundity, development and survival we conducted a no-choice field cage experiment in which Osmia lignaria were provided blueberry (Vaccinium corymbosum), phacelia (Phacelia tanacetifolia) and white clover (Trifolium repens) that had been previously exposed to either extreme heat (37.5°C) or normal temperatures (25°C) for 4 h during early bloom. Despite a similar number of open flowers and floral visitation frequency between the two treatments, female bees provided with heat-stressed plants laid approximately 70% fewer eggs than females provided with non-stressed plants. Their progeny received similar quantities of pollen provisions between the two treatments, yet larvae consuming pollen from heat-stressed plants had significantly lower survival as larvae and adults. We also observed trends for delayed emergence and reduced adult longevity when larvae consumed heat-stressed pollen. This study is the first to document how short, field-realistic bursts of extreme heat exposure to flowering host plants can indirectly affect bee pollinators and their offspring, with important implications for crop pollination and native bee populations. [ABSTRACT FROM AUTHOR]

Advancements in agricultural production have seen the rapid adoption of protected cropping systems globally. Such systems have been optimized for plant growth and efficiency, with little understanding of the potential impacts to key insect pollinators. Here, we investigate the effect of bird netting and polythene rain covers on the health and performance of honey bees (Apis mellifera L.) during the pollination of sweet cherry crops. Over two consecutive seasons, 12 full‐strength colonies were equipped with tagged bees and radio frequency identification (RFID) systems. The colonies were equally divided between open control, bird netted and polythene (semi‐permanent VOEN in 2019 and retractable Cravo in 2020) groups. Over 1300 individual bees were monitored for the duration of the commercial pollination period to determine behavioural parameters such as foraging commencement age, number and duration of trips and overall survival. Bees began foraging within the optimum age range (mean 15.7–24.1 days) under all covering types, with little indication of prolonged stress or increased mortality during the short season. Polythene covers (VOEN & Cravo) were found to significantly increase the total time needed for bees to orientate successfully. Once orientated, bees placed under covers conducted up to 155% more foraging trips, with a longer cumulative duration. Covering type was found to significantly impact the amount and type of pollen collected, with the most restrictive system (VOEN) yielding the highest proportion of cherry pollen. Overall, we found little evidence to suggest that the tested protective covers have a detrimental impact to honey bee foraging in cherry crops. [ABSTRACT FROM AUTHOR]

Hybrid vegetable varieties have become essential for global agricultural production, offering key advantages for yield, quality and disease resistance. The production of hybrid seeds is however limited by pollination challenges, with these systems commonly associated with unattractive and low‐quality floral resources, isolated growing environments and frequent insecticide applications.Here, we utilise commercial carrot seed crops to investigate the impact of hybrid pollination on the behaviour of the honey bee (Apis mellifera).Six full‐strength bee colonies were equipped with solar powered radio frequency identification systems and over 900 tagged bees per season. These colonies were deployed to commercial hybrid seed crops over two consecutive seasons. The colonies were allocated to either an on‐crop or off‐crop group. Individual bees were autonomously monitored for the pollination period to assess key parameters such as survival, age at foraging and the number and duration of orientation and foraging trips.Hybrid carrots were found to have a significant impact on bee foraging behaviour. Bees situated on the carrot crop undertook less frequent yet longer foraging trips, resulting in less total time outside of the colony compared to off‐crop bees. However, bees placed in carrot fields survived to an older age, orientated successfully, became foragers later and collected more pollen by weight, despite only 2% originating from carrot. We hope that the improved behavioural understanding can be utilised to enhance both pollinator health and hybrid seed production globally. [ABSTRACT FROM AUTHOR]

Global demand for vegetable oil is projected to expand to 28 Mt by 2028. Oilseed rape (OSR) is the predominant oilseed crop in Europe. Its nutritional value is determined by seed oil content and fatty acids (FAs) composition. Insect pollination increases seed oil content, however, its benefit on FAs composition remains unknown. In this study, we address this gap by investigating the variation of OSR seed oil content and FAs composition along a gradient of bee abundance in farmed OSR fields. We used a pollinator exclusion experiment to disentangle the contribution of pollination processes, i.e. wind, self and insect pollination. We show that bees improved OSR nutritional value by increasing amount of poly-unsaturated FAs and decreasing the amount saturated and trans-saturated FAs. In addition, oil content was higher in seeds with than without access to pollinators. Our study provides for the first time, to the best of our knowledge, evidence that insect pollination enhances the quality value of OSR oil by affecting FAs composition. Such effect implies potential negative consequences with any further decline of pollinator abundance. More investigations are also needed to better understand the mechanisms by which insect pollination affects FAs composition, and the way to enhance such mechanisms. [ABSTRACT FROM AUTHOR]

Abstract Animal pollination plays a key role in global agricultural production and especially of monoecious crops, which are essentially dependent on pollinators. The West Indian gherkin fruit (Cucumis anguria L., Cucurbitaceae) is a monoecious vegetable adaptable to adverse abiotic conditions, resistant to diseases, and rich in minerals and vitamins, thus being a relevant alternative for improving nutritional security of socioeconomically vulnerable populations. The knowledge on the influence of pollination and of specific pollinators on chemical characteristics of fruits would help pollinators’ management, but it is still poorly understood. In this study we investigated the influence of pollination on quantitative and qualitative aspects of fruits fruits of West Indian gherkin fruits (Cucumis anguria L., Cucurbitaceae) in the Brazilian semi-arid region. Data on pollination biology and on fruits resulted from controlled crosses (open-OP, cross-CP and Apis mellifera Linnaeus, 1758 pollinations) were compared among crosses: number, length, weight, number of seeds, firmness and chemical traits related to flavor and shelf life. Flowers were pollinated by four bee species, and Apis mellifera was the most frequent. followed by two native bee species. OP and A. mellifera resulted in more fruits than CP. Fruits resulting from OP were heavier than CP and had similar weight when compared to A. mellifera. The other variables did not differ between treatments. The better performance of OP and A. mellifera when compared to CP is probably related to the xenia, i.e., the influence of tissues bearing paternal genes (pollen and pollen tube) in maternal tissues. OP and A. mellifera experiments apparently resulted in the deposition of a greater genotypic diversity of the pollen loads when compared to CP. This result is also explained by the higher functional diversity of pollinators related to OP when compared to CP. This study not only elucidates immediate impacts on yield but also emphasizes the deeper connections between floral biology, pollinator diversity, and sustainable crop production, once West Indian gherkin profit was enhanced by bee pollination.

Crop–pollinator interactions are essential for world food security. Studying crop pollination from a network approach allows identification of target pollinators for conservation and management, and gaps in our knowledge. Solanaceae represents the third highest ranked family based on economic value, and its production is highly improved by animal pollination. This study aimed to integrate global data on solanaceous crop pollination and analyse the interaction patterns using a meta‐network approach. Our questions were: (i) how are interactions structured and what are the structuring roles of species; and (ii) what are the main gaps in our knowledge?Data were obtained through a systematic review of the main scientific databases. The network structure was described using connectivity and modularity calculations, and the role of species using centrality metrics.The 251 pollinator species reported were in seven orders, mainly Hymenoptera (84.9%). The generalists Bombus and Apis species were the most common pollinators. The meta‐network was modular, and all modules mostly included bees. Most species were peripherals, around 12% were connectors, and there were no module hubs. Apis mellifera was the only network hub (supergeneralist).The most important pollinators are the most managed pollinators worldwide; however, many native species play a role in structuring the meta‐network. Main gaps include species of importance to pepper pollination, lack of species‐specific identification, and the need for more robust experimental studies evaluating the pollination efficiency of native, manageable bees. [ABSTRACT FROM AUTHOR]

Among the ground-nesting bees are several proven crop pollinators, but only the alkali bee (Nomia melanderi) has been successfully managed. In <80 years, it has become the world's most intensely studied ground-nesting solitary bee. In many ways, the bee seems paradoxical. It nests during the torrid, parched midsummer amid arid valleys and basins of the western United States, yet it wants damp nesting soil. In these basins, extensive monocultures of an irrigated Eurasian crop plant, alfalfa (lucerne), subsidize millions of alkali bees. Elsewhere, its polylectic habits and long foraging range allow it to stray into neighboring crops contaminated with insecticides. Primary wild floral hosts are either non-native or poorly known. Kleptoparasitic bees plague most ground nesters, but not alkali bees, which do, however, host other well-studied parasitoids. Building effective nesting beds requires understanding the hydraulic conductivity of silty nesting soils and its important interplay with specific soil mineral salts. Surprisingly, some isolated populations endure inhospitably cold climates by nesting amid hot springs. Despite the peculiarities and challenges associated with its management, the alkali bee remains the second most valuable managed solitary bee for US agriculture and perhaps the world. [ABSTRACT FROM AUTHOR]

Phenological overlap between crop flowering and pollinators is a crucial trait for the pollination of more than 75% of the world's crops. However, crop management rarely considers the seasonal aspect of plant–pollinator mutualism. Here, we investigate the phenological overlap between crops and pollinators and how it affects pollination and fruit production.We measured the abundance and richness of native and non‐native pollinators visiting raspberry flowers at two different times during the flowering season (i.e. early and late flowering periods) and examined their effects on crop yield in 16 fields.The community of pollinators foraging on raspberry flowers was more diverse and dominated by native pollinators during the early flowering period when most native plant species were flowering. Later in the season, when native flower resources declined in the surrounding environment, raspberry flowers were visited mainly by two non‐native bees: managed honeybees and the invasive bumblebee Bombus terrestris.Pollinator contribution to raspberry yield was twice as high in the early flowering period compared to the late period (61% vs. 31% increase in drupelet set respectively). Flower damage caused by extremely high visitation frequencies by non‐native bees in the late period was six times higher than in the early flowering period (30% vs. 5% of damaged flowers respectively).Synthesis and applications. Providing sufficient pollen and nectar resources to support wild pollinators over extended periods in agricultural landscapes can contribute to crop pollination and ensure high fruit weight and quality. This can be achieved by restoring natural and semi‐natural areas near crop fields with native, long‐flowering plant species. Growers and crop breeding programmes should consider selecting flowering times that coincide with periods of high diversity or abundance of native pollinators to reduce dependence on managed pollinators. [ABSTRACT FROM AUTHOR]

Assessing the relative contributions of different pollinator taxa to pollination services is a central task in both basic eco‐evolutionary research and applied conservation and agriculture. To that end, many studies have quantified single‐visit pollen deposition and visitation frequency, which together determine a pollinator species' rate of conspecific pollen delivery. However, for plant species that require or benefit from outcrossing, pollination service quality further depends upon the ratio of outcross to self‐pollen deposited, which is determined by two additional pollinator traits: pollen carryover and movement patterns among genetically compatible plant individuals. Here, we compare the pollination capacities of managed honey bees, native bumble bees, and native mining bees in apple—a varietally self‐incompatible commercial crop—when pollen carryover and pollinator movement patterns are considered. We constructed simulation models of outcross pollen deposition parameterized using empirically measured single‐visit pollen deposition, visitation frequency, and probabilities of intertree movement exhibited by each pollinator type, as well as pollen carryover patterns simulated based on parameters reported in the literature. In these models, we also explicitly specified the spatial relationships among cross‐compatible trees based on field‐realistic orchard layout schemes. We found that estimated pollination service delivery was considerably reduced for all pollinator types when pollen carryover and pollinator movement patterns were considered, as compared to when only single‐visit pollen deposition and visitation frequency were considered. We also found that the performance of different pollinator types varied greatly across simulated orchard layout schemes and pollen carryover scenarios, including one instance where bumble and mining bees reversed their relative rankings. In all simulations, native bumble and mining bees outperformed managed honey bees in terms of both outcross pollen delivery per unit time and per flower visited, with disparities being greatest under scenarios of low pollen carryover. We demonstrate the degree to which pollination studies may reach inaccurate conclusions regarding pollination service delivery when pollen carryover and pollinator movement patterns are ignored. Our finding of the strong context dependence of pollination efficiency, even within a single plant–pollinator taxon pair, cautions that future studies in both basic and applied pollination biology should explicitly consider the ecological context in which pollination interactions take place. [ABSTRACT FROM AUTHOR]

Avocado is a pollinator-dependent crop rich in fiber, monounsaturated oils, vitamins, and minerals, which is seeing an increase in global demand. While some studies have shown that insect pollination improves avocado fruit set, the effects of pollinators on fruit quality and the nutritional profile remain unclear. Furthermore, it remains untested whether a potential pollination deficit can be compensated by the supplementation of farms with extra pollinators. We quantified the contribution of insect pollination on fruit and seed weight, and oil, protein, carbohydrate, and phytochemical (flavonoid and phenolics) contents, and assessed if the supplementation of pollinators on farms can improve fruit parameters. The experiment was conducted in 36 smallholder avocado farms of which 18 farms were supplemented with two Apis mellifera bee hives, while 18 were used as controls. Four manipulative pollination treatments were conducted: hand, open, self- and wind pollination. We observed that avocado fruit weight was significantly higher (213.7 g) for insect pollinated flowers than in case of wind- (107.8 g) or self-pollination (95.1 g). Insect pollination resulted in heavier seeds (29.5 g) as well as higher oil contents, clearly showing that insect pollination was required to reach a high seed yield and quantity of oil. Honey bee supplementation on farms enhanced the avocado fruit weight by 18%, and increased avocado oil content by 3.6%. As the marketability of avocado directly depends on fruit size and oil content, a sustainable management of bee communities may be of key importance for the long-term profitability of avocado agriculture. [ABSTRACT FROM AUTHOR]

Despite growing awareness of the importance of monitoring wild crop pollinators worldwide, there are still few reports, especially in East Asia. Considering ongoing global warming may change the distribution range and diurnal activity of pollinators, it is necessary to describe current geographic and diurnal patterns. We clarified pollinators of Cucurbita maxima Duchesne (Cucurbitales: Cucurbitaceae) in three geographically distinct (>350 km, minimum) areas in Japan, focusing on diurnal variation. Apis mellifera L. (Hymenoptera: Apidae) and Halictidae (Hymenoptera) were observed in all of the experimental gardens. Apis cerana japonica Radoszkowski (Hymenoptera: Apidae) were mainly observed in Mie and Kagoshima, while Bombus diversus diversus Smith (Hymenoptera: Apidae) were observed only in Ibaraki. The peak time of flower visits depended both on bee taxa and area, and interestingly, did not necessarily synchronize with the timing of the highest pollen loads and the probability of stigma contact. In particular, visits and probability of contacting stigmas of Halictidae tended to increase as time passed, whereas pollen grains on their bodies sharply decreased with time; only a few individuals of Halictidae that visit early can become effective pollinators. There were no differences in yields between supplementary hand and natural pollination in all areas, and flower‐enclosure experiments using different mesh sizes clarified that small insects that can go across an approximately 4‐mm mesh may not transport sufficient pollen for fruit set. Our study demonstrated that pollination effectiveness, which is usually regarded as a static value, within a taxon can fluctuate in the space of just several hours. Considering such diurnal patterns can be altered by climate change, we need to carefully monitor the diurnal temporal patterns of pollinators worldwide. [ABSTRACT FROM AUTHOR]

Since mid‐1990s, concerns have increased about a human‐induced "pollination crisis." Threats have been identified to animals that act as plant pollinators, plants pollinated by these animals, and consequently human well‐being. Threatening processes include loss of natural habitat, climate change, pesticide use, pathogen spread, and introduced species. However, concern has mostly been during last 10–15 years and from Europe and North America, with Australasia, known as Down‐Under, receiving little attention. So perhaps Australasia has "dodged the bullet"? We systematically reviewed the published literature relating to the "pollination crisis" via Web of Science, focusing on issues amenable to this approach. Across these issues, we found a steep increase in publications over the last few decades and a major geographic bias towards Europe and North America, with relatively little attention in Australasia. While publications from Australasia are underrepresented, factors responsible elsewhere for causing the "pollination crisis" commonly occur in Australasia, so this lack of coverage probably reflects a lack of awareness rather than the absence of a problem. In other words, Australasia has not "dodged the bullet" and should take immediate action to address and mitigate its own "pollination crisis." Sensible steps would include increased taxonomic work on suspected plant pollinators, protection for pollinator populations threatened with extinction, establishing long‐term monitoring of plant–pollinator relationships, incorporating pollination into sustainable agriculture, restricting the use of various pesticides, adopting an Integrated Pest and Pollinator Management approach, and developing partnerships with First Nations peoples for research, conservation and management of plants and their pollinators. Appropriate Government policy, funding and regulation could help. [ABSTRACT FROM AUTHOR]

Simple Summary: Urban agriculture is a sustainable form of crop production for city-dwellers that requires insect pollinators to produce fruits and vegetables. However, few studies have tested whether urban pollinators are able to support the production of these urban crops. We carried out a study in an urban area near Paris (France) to test whether pollinators present in an urban environment contributed to the production of strawberries. From observational pollinator surveys, we found only wild pollinators visiting strawberry flowers, i.e., no honey bees were observed despite the presence of beehives nearby. We found that fruits were larger when pollinators could visit the flowers. Our results suggest that wild pollinators present in this urban environment are able to support strawberry production in an urban agricultural context. Pollination services provided by a diversity of pollinators are critical in agriculture because they enhance the yield of many crops. However, few studies have assessed pollination services in urban agricultural systems. We performed flower–visitor observations and pollination experiments on strawberries (Fragaria × ananassa) in an urban area near Paris, France, in order to assess the effects of (i) insect-mediated pollination service and (ii) potential pollination deficit on fruit set, seed set, and fruit quality (size, weight, and malformation). Flower–visitor observations revealed that the pollinator community solely comprised unmanaged pollinators, despite the presence of beehives in the surrounding landscape. Based on the pollination experiments, we found that the pollination service mediated by wild insects improved the fruit size as a qualitative value of production, but not the fruit set. We also found no evidence of pollination deficit in our urban environment. These results suggest that the local community of wild urban pollinators is able to support strawberry crop production and thus plays an important role in providing high-quality, local, and sustainable crops in urban areas. [ABSTRACT FROM AUTHOR]

British Columbia beekeepers, like many beekeepers around the world, are currently facing declines in honey bee health and high overwinter colony losses. To better understand the economics and the cycle of yearly colony loss and replacement of this critical agricultural industry, we collected and analyzed survey data on beekeeping costs and returns. Forty British Columbia beekeepers provided details about revenue sources, variable costs, capital costs, and investments. Ten surveyed beekeepers managed between 1 and 9 colonies, 10 managed between 10 and 39 colonies, 9 managed between 40 and 100 colonies, 5 managed between 101 and 299 colonies, 3 managed between 300 and 699 colonies, and 3 managed 700 colonies or more. The data was used to calculate beekeeping profit and to parameterize a model that explores the economic impact of colony loss rates and replacement strategies. Survey results show that when the data is aggregated, revenues exceed costs for beekeeping operations in British Columbia with a per colony profit of $56.92 or $0.87 per pound of honey produced. Surveyed operations with fewer than 100 colonies have negative profits, while operations with 100–299 colonies have positive profits. Surveyed operations in the Cariboo, North Coast, and Okanagan regions have the highest profits while surveyed operations in the Peace region have the lowest profits. Profit modeling shows that replacing losses with packages generates lower profit than replacing losses with split colonies. Our modeling shows that operations that diversify their revenue to include bee sales and commercial pollination accrue higher profits and can withstand higher winter loss rates. [ABSTRACT FROM AUTHOR]

Cucurbita pepo crops (pumpkin, squash) are entirely dependent upon insect pollinators for reproduction. In Ontario, Canada, their most important pollinator is the hoary squash bee (Eucera pruinosa), a wild ground-nesting, solitary bee whose only source of pollen in the region is Cucurbita crops. As such, in this context, we have a unique opportunity to study pollen partitioning in a cropping system in which a wild bee is the main pollinator. To evaluate pollen partitioning in the system, we measured pollen production by the crop, the pollen lost as waste due to the activities of bees in staminate flowers, pollen loads collected by female squash bees, and the number of pollen grains in fully provisioned hoary squash bee nest cells, and we compared these to the crop’s pollination requirements as reported in the literature. From the perspective of both plant and bee reproduction, about 13% of the pollen produced by staminate acorn squash flowers was wasted, but it may be harvested by other organisms like ants. After waste is accounted for, about 9% of the pollen left is needed for plant reproduction leaving the remaining 91% available for hoary squash bee reproduction. We also evaluated the mass of pollen a female hoary squash bee could carry in a single foraging trip relative to her own body mass (~4%). The information contained here is useful for understanding the relationship between a crop and an oligolectic wild bee species or to set up controlled, field realistic experiments involving the hoary squash bee.

Abstract Despite growing awareness of the importance of monitoring wild crop pollinators worldwide, there are still few reports, especially in East Asia. Considering ongoing global warming may change the distribution range and diurnal activity of pollinators, it is necessary to describe current geographic and diurnal patterns. We clarified pollinators of Cucurbita maxima Duchesne (Cucurbitales: Cucurbitaceae) in three geographically distinct (>350 km, minimum) areas in Japan, focusing on diurnal variation. Apis mellifera L. (Hymenoptera: Apidae) and Halictidae (Hymenoptera) were observed in all of the experimental gardens. Apis cerana japonica Radoszkowski (Hymenoptera: Apidae) were mainly observed in Mie and Kagoshima, while Bombus diversus diversus Smith (Hymenoptera: Apidae) were observed only in Ibaraki. The peak time of flower visits depended both on bee taxa and area, and interestingly, did not necessarily synchronize with the timing of the highest pollen loads and the probability of stigma contact. In particular, visits and probability of contacting stigmas of Halictidae tended to increase as time passed, whereas pollen grains on their bodies sharply decreased with time; only a few individuals of Halictidae that visit early can become effective pollinators. There were no differences in yields between supplementary hand and natural pollination in all areas, and flower‐enclosure experiments using different mesh sizes clarified that small insects that can go across an approximately 4‐mm mesh may not transport sufficient pollen for fruit set. Our study demonstrated that pollination effectiveness, which is usually regarded as a static value, within a taxon can fluctuate in the space of just several hours. Considering such diurnal patterns can be altered by climate change, we need to carefully monitor the diurnal temporal patterns of pollinators worldwide.

Abstract Since mid‐1990s, concerns have increased about a human‐induced “pollination crisis.” Threats have been identified to animals that act as plant pollinators, plants pollinated by these animals, and consequently human well‐being. Threatening processes include loss of natural habitat, climate change, pesticide use, pathogen spread, and introduced species. However, concern has mostly been during last 10–15 years and from Europe and North America, with Australasia, known as Down‐Under, receiving little attention. So perhaps Australasia has “dodged the bullet”? We systematically reviewed the published literature relating to the “pollination crisis” via Web of Science, focusing on issues amenable to this approach. Across these issues, we found a steep increase in publications over the last few decades and a major geographic bias towards Europe and North America, with relatively little attention in Australasia. While publications from Australasia are underrepresented, factors responsible elsewhere for causing the “pollination crisis” commonly occur in Australasia, so this lack of coverage probably reflects a lack of awareness rather than the absence of a problem. In other words, Australasia has not “dodged the bullet” and should take immediate action to address and mitigate its own “pollination crisis.” Sensible steps would include increased taxonomic work on suspected plant pollinators, protection for pollinator populations threatened with extinction, establishing long‐term monitoring of plant–pollinator relationships, incorporating pollination into sustainable agriculture, restricting the use of various pesticides, adopting an Integrated Pest and Pollinator Management approach, and developing partnerships with First Nations peoples for research, conservation and management of plants and their pollinators. Appropriate Government policy, funding and regulation could help.

For most food crops the identity and efficiency of pollinators across key growing regions remains a significant knowledge gap that needs to be addressed before we can develop crop-specific approaches for pollination service delivery. Here, we conducted a systematic literature review and meta-analysis on watermelon (Citrullus lanatus (Thunb. Matsum. & Nakai)), a globally important fruit crop, to identify the floral visitors and their efficiency across different growing regions. We found that 265 insect species visit watermelon flowers (including 5 orders, 18 families and 75 genera) across 17 countries and 6 continents. Bees and flies were the most abundant flower visitors overall, but show distinct regional differences. Honey bees were the majority visitor in 53% of growing regions (range: 0 – 94%), whilst wild bee species were more abundant in 42% of regions (range: 3.4 – 100%). Honey bees and other bees were equally effective at depositing pollen on stigmas, but varied in effectiveness for fruit set and seed set. Pollination data from global studies appear to be limited for the largest-scale watermelon producers, namely: China, Turkey, and India, with the majority (56%) of data available from North America. This synthesis identified four key themes for improving pollination in watermelon: increasing honey bee densities on crops where local polices and environmental conditions are suitable; introducing other managed pollinators; identifying key wild pollinator taxa to encourage within crops; and improving local and landscape management practices to support pollinators.

Mason bees (Osmia spp.) are efficient fruit tree pollinators that can be encouraged to occupy and breed in artificial nesting material. In sweet cherry orchards, they are occasionally used as an alternative managed pollinator as a replacement for or in addition to honey bees (Apis mellifera). Yet, the lack of practical guidelines on management practices, for example optimal stocking rates, for both mason bee nesting material and honey bees might compromise pollination service provision. In this study, we assessed the relationship between stocking rates (honey bee hives and mason bee nesting material) and the abundance of honey bees and mason bees in 17 sweet cherry (Prunus avium) orchards in Central Germany. We furthermore performed a pollination experiment to explore the interactive effect of mason bees and honey bees on sweet cherry fruit set. In the orchards, both honey bee and mason bee abundance increased with increasing stocking rates of hives or nesting material, respectively. Honey bee abundance increased linearly with stocking rates. In contrast, mason bee abundance asymptoted at 2–3 nesting boxes per ha, beyond which more boxes resulted in little increase in visitation rate. Our pollination experiment demonstrated that orchards were pollen limited, with only 28% of insect‐pollinated flowers setting fruit versus 39% of optimally hand‐pollinated flowers. Honey bees and mason bees enhanced sweet cherry fruit set, but only when both were present and not when either was present alone in an orchard. Our findings demonstrate that offering nesting material for mason bees and employing honey bee hives can enhance bee abundance in sweet cherry orchards. By increasing honey bee abundance in combination with enhanced mason bee abundance, farmers can substantially boost fruit set and potentially sweet cherry yield. To enhance pollination services, farmers should consider the benefits of increasing pollinator biodiversity as an immediate benefit to improve crop yields. [ABSTRACT FROM AUTHOR]

Summary: Maintenance of a diverse pollinator community helps ensure resilience in pollination services. Fragments of woody and grassy vegetation in the vicinity of croplands have been shown to encourage the presence of crop‐pollinating bees. However, to date, little attention has been given to the management practices that may enhance the presence of bees in such fragments. We investigated how the maintenance of remnant forest fragments adjacent to apple orchards in South Australia affects floral resources and native bee communities. The fragments had been subject to either (a) fire (assessments three years post‐burn), (b) cattle grazing under trees and (c) low maintenance management (>20 years not grazed or burnt). Plant communities were sampled along transects in plots. Bee communities were sampled using hand netting. We fitted generalised linear mixed models to investigate differences in plant and bee diversity between treatments and to elucidate the effect of plant diversity on bee diversity. We compared plant and bee community composition among treatments using non‐metric multidimensional scaling and conducted network analysis to measure the robustness of plant‐pollinator interactions to the removal of species. Both floral resource abundance and bee diversity were higher in burnt and low‐maintenance fragments than in grazed fragments. Bee species richness was positively associated with plant species richness. The species richness of bees that visit apple flowers was positively associated with flower abundance but not with floral species richness. Plant‐pollinator networks in grazed sites had fewer links per species and a higher proportion of realised links than those under other management practices. However, the resilience of pollinator networks did not differ significantly between management practices. Thus, controlled burns or low‐maintenance management of forest fragments appear to be the most suitable landscape management practices to support apple pollinating bees. Burning requires consideration of additional ecological consequences, such as the conservation of fire‐sensitive species and specialist woodland fauna. Cattle grazing adjacent to orchards results in simplified bee communities and pollination networks and is not recommended if pollination services are required for adjacent land uses. This information can benefit orchardist as well as managers of fragments of native vegetation adjacent to orchard crops. [ABSTRACT FROM AUTHOR]

An increasing number of farmland initiatives aim to aid biodiversity conservation through alternative farming practices such as nature-inclusive farming. However, these approaches frequently lead to trade-offs between biodiversity conservation and crop yield. For example, buckwheat (Fagopyrum esculentum) is a melliferous crop that flowers for a long period in the summer when nectar in agricultural areas is generally scarce, and buckwheat cultivation could therefore contribute to wild pollinator conservation. However, honeybees (Apis mellifera) are placed to ensure sufficient crop pollination, which potentially increases resource competition with wild pollinators in and around the crop. Here, we have studied this trade-off by surveying pollinators in and around 16 small-scale (∼1 ha) flowering buckwheat fields and we determined the contribution of pollinator density to crop yield in a nature-inclusive farming project. We found that the buckwheat pollinator community was diverse, albeit dominated by honeybees. We found no clear indications of resource competition between honeybees and wild pollinators within the buckwheat fields. Honeybee density in the surroundings was generally low, and increased minimally during honeybee-hive placement. While densities of honeybees decreased non-linearly over the day in buckwheat fields, they did not (temporarily) move into the surroundings of the field, suggesting limited competition for resources with wild pollinators. Crop yield was largely dependent on crop pollinator density, notably of honeybees, and to a lesser extent crop biomass (as a proxy for agricultural management). Our results show that buckwheat cultivation fits well within nature-inclusive farming if some simple precautionary measures are being taken, such as limiting the honeybee-hive densities and placing hives only during the main flowering period. The introduction of buckwheat cultivation into crop rotation could then contribute to fill an important nectar gap in the summer, which potentially boosts wild pollinator populations in the long term.

Introduction: Bees capable of performing floral sonication (or buzz-pollination) are among the most effective pollinators of blueberries. However, the quality of pollination provided varies greatly among species visiting the flowers. Consequently, the correct identification of flower visitors becomes indispensable to distinguishing the most efficient pollinators of blueberry. However, taxonomic identification normally depends on microscopic characteristics and the active participation of experts in the decision-making process. Moreover, the many species of bees (20,507 worldwide) and other insects are a challenge for a decreasing number of insect taxonomists. To overcome the limitations of traditional taxonomy, automatic classification systems of insects based on Machine-Learning (ML) have been raised for detecting and distinguishing a wide variety of bioacoustic signals, including bee buzzing sounds. Despite that, classical ML algorithms fed by spectrogramtype data only reached marginal performance for bee ID recognition. On the other hand, emerging systems from Deep Learning (DL), especially Convolutional Neural Networks (CNNs), have provided a substantial boost to classification performance in other audio domains, but have yet to be tested for acoustic bee species recognition tasks. Therefore, we aimed to automatically identify blueberry pollinating bee species based on characteristics of their buzzing sounds using DL algorithms. Methods: We designed CNN models combined with Log Mel-Spectrogram representations and strong data augmentation and compared their performance at recognizing blueberry pollinating bee species with the current state-of-the-art models for automatic recognition of bee species. Results and Discussion: We found that CNN models performed better at assigning bee buzzing sounds to their respective taxa than expected by chance. However, CNN models were highly dependent on acoustic data pre-training and data augmentation to outperform classical ML classifiers in recognizing bee buzzing sounds. Under these conditions, the CNN models could lead to automating the taxonomic recognition of flower-visiting bees of blueberry crops. However, there is still room to improve the performance of CNN models by focusing on recording samples for poorly represented bee species. Automatic acoustic recognition associated with the degree of efficiency of a bee species to pollinate a particular crop would result in a comprehensive and powerful tool for recognizing those that best pollinate and increase fruit yields. [ABSTRACT FROM AUTHOR]

In response to anthropogenic environmental change, the cues that animals use throughout their lifecycle to optimize fitness may become unreliable, resulting in an ecological trap.Here we investigated whether commercial bumble bee Bombus impatiens colonies managed for early spring crop pollination act as ecological traps for wild nest‐searching Bombus queens by subverting their natural nest usurpation behaviour.An average of 10 dead wild queens were recovered from each standard colony during the 2‐week period of the experiment, but colonies with queen excluders were successful in preventing wild queen deaths. The use of queen excluders did not impact colony performance in terms of resident queen survival, colony reproduction, colony weight gain or worker body size.Sites where wild nest‐searching queens were small had higher rates of failed usurpation, suggesting smaller‐sized queens are disproportionately at risk from failed usurpation. Furthermore, sites where commercial colonies without queen excluders were introduced for spring crop pollination had fewer bumble bee visits to a later‐blooming crop compared to sites without commercial colonies.Synthesis and applications. Our findings reveal a novel mechanism by which commercial colonies can negatively impact wild bumble bee populations and their pollination services. At the same time, we demonstrate a simple and inexpensive risk mitigation tool—a queen excluder—was 100% effective at eliminating this risk without compromising colony performance. Commercial colonies used outdoors during the bumble bee nest‐searching period should be fit with queen excluders to prevent negative impacts on wild pollinator communities and their services. [ABSTRACT FROM AUTHOR]

Eggplant is an important vegetable crop grown worldwide. Eggplant flowers have typical poricidal anthers which need a vibratory motion for effective pollination. This study was conducted to identify the major flower visitors and their effect on eggplant pollination/fruit set. Nine different species of bees visited eggplant flowers. The pollination efficiency index of the buzz pollinating bee, Amegilla violacea, was found to be the highest and was the most efficient pollinator of eggplant. The fruit set, fruit weight, and the number of seeds per fruit increased with an increase in the level of anther cone bruising and with a greater number of buzzes made by the native bee. Our study confirmed the distinct role of native sonicating bees and emphasizes the need to conserve the native bee fauna for enhancing fruit and seed set in eggplant. [ABSTRACT FROM AUTHOR]

Simple Summary: Improving floral margins around crops can help to maintain and conserve populations of wild pollinators, mainly insects, in agroecosystems, and can improve the ecosystem services they provide, such as pollination of many crops and wild plants. Some crops, such as melon, depend on insects for reproduction, which is why they are at risk, as pollination services are declining. Our study shows that the implementation of margins around melon crops showed a positive effect on the abundance and richness of pollinating insects in general, which was stronger in the second year after establishment. Specifically, managed shrubby margins favored the populations of Syrphidae, Andrenidae, Apidae (excl. Apis mellifera), and other pollinator groups, and bee richness, suggesting that this type of margin increases pollinators' activity to a greater extent than the other two types of margins (managed and unmanaged herbaceous margins). However, the type of margin did not show any added advantages for melon yield. Melon is among the most consumed fruits in the world, being a crop that depends almost entirely on insects for its reproduction, which is why it is especially sensitive to declining pollination services. Restoration and maintenance of hedgerows and agricultural borders around crops are generally carried out by sowing flowering herbaceous plants or establishing shrubby species; however, a cost-effective and lower-maintenance alternative for farmers could be as simple as allowing vegetation to regenerate naturally without any management actions. This work aimed to test the effects of three different types of margins (managed herbaceous, managed shrubby, and unmanaged herbaceous) on the overall abundance and richness of wild pollinators in melon crops. The work was performed in three localities in southern Spain over two years. Pollinators were monitored visually using 1 × 1 m sampling squares and pan traps within melon fields. Moreover, crop yield was estimated by measuring fruit weight and the number of seeds. In general, higher abundances of pollinators were observed in melon fields during the second year. In addition, the abundances of Syrphidae, Andrenidae, Apidae (excl. Apis mellifera), and pollinators other than bees, belonging to the orders Diptera, Coleoptera, Hymenoptera, and Lepidoptera, showed higher values in melon fields with shrubby margins than in fields with herbaceous margins (managed or unmanaged). However, no effect of floral margins on the yield of melon crops was found. [ABSTRACT FROM AUTHOR]

Acknowledging species interactions is essential for managing diversity in complex agricultural systems. To understand the neighbouring plant effect on flower number and size, we performed a greenhouse experiment with paired pots in three treatments: focal plant (common bean/courgette) with conspecific neighbour, heterospecific neighbour or empty pot. Common beans without neighbours produced more flowers than when accompanied. Common bean with conspecific neighbours produced more flowers than with heterospecific neighbours, with larger standard petals. Courgettes with heterospecific neighbours had flowers with deeper corollas than with conspecific neighbours. To understand effects on visitation and production, we performed a field experiment comparing courgette monoculture, common bean monoculture and three intercroppings, varying the crop ratio. Species composition of floral visitors differed significantly between monoculture and intercropping. The six plots (6/21) with highest diversity were intercropping. Intercropping courgette and common bean can change floral morphology and alter plant–pollinator interactions in the agroecosystem, enhancing pollinator diversity. this article provides an empirical basis for the adoption of multispecies consortia in agroecosystems as an instrument to foster local pollinator biodiversity; it provides empirical evidence that neighbouring plant species identity can have an effect on flowers' morphological traits, which may be an important consideration when planning and managing agroecosystems; it reinforces that diversified crop systems, with known ecological advantages, can be grown without production loss; it supports that scientific development towards more sustainable food systems should include traditional knowledge systems. [ABSTRACT FROM AUTHOR]

Simple Summary: Insect pollinators such as bees contribute to crop production, food security, ecosystem stability and biodiversity in agroecosystems. However, intensification of agricultural practices jeopardizes pollination services in agricultural landscapes mainly through the decline in flower resources for pollinators in farmlands. The study examines a scheme to provide floral resources for insect pollinators in apple orchards potentially contributing to their conservation and enhancing crop pollination. For this reason, flowering mixtures including legume landraces were sown in patches inside apple orchards and compared to the orchard's weed flora in respect of attraction of pollinators. Pollinators recorded on the sown and wild plant patches were honey bees, wild bees, syrphids and beeflies. The most abundant pollinator of apple was the honey bee but wild bees were also recorded. The sown mixture attracted greater numbers of pollinators and more wild bee taxa compared to the wild plants, but it did not have an effect on pollinators visiting apple flowers. Flowering patches with mixtures of suitable plants in groundcover can enhance pollinator conservation in apple orchards. Apples depend on insect pollination but intensification of agriculture jeopardizes pollination services in agroecosystems. Concerns about the dependency of crop pollination exclusively on honey bees increase the interest in agricultural practices that safeguard wild pollinators in agroecosystems. The purpose of the study was to assess the potential of floral resource provision in apple orchards to enhance the conservation of hymenopterous pollinating insects and potentially the pollination service to the crop. For this reason, flowering plant mixtures sown in patches inside apple orchards were tested against wild plant patches. Pollinator taxa recorded on the sown and wild plant patches were honey bees, wild bees (Andrena, Anthophora, Eucera, Halictus, Lasioglossum, Megachilidae on both; Systropha only on wild plants; Bombus, Hylaeus, Sphecodes, Nomada, Xylocopa only on sown mixture), syrphids, bee flies. The most abundant pollinator of apple was A. mellifera but wild bees were also recorded (Andrena, Anthophora, Bombus, Xylocopa, Lasioglossum, Megachilidae). The sown mixture attracted a more diverse taxa of pollinators and in greater numbers compared to the weed flora, but it did not have an effect on pollinators visiting apple flowers. Groundcover management with patches of suitable flowering mixtures can enhance pollinator conservation in apple orchards. [ABSTRACT FROM AUTHOR]

In agricultural landscapes, uncultivated habitat patches may have a focal role in supporting communities of ecosystem service providers. However, little is known on the variances among different types of uncultivated habitat patches in providing resources and maintaining populations of these beneficial organisms. We studied wild bee communities in natural and semi-natural uncultivated patches embedded in semi-arid Mediterranean agricultural landscapes. We investigated the effects of local- and landscape-scale land-use characteristics, as well as their interactions, on bee diversity, functional composition, and forage and nesting resources. Most bee community parameters were affected by both local- and landscape-scale characteristics, but no significant interactions were found among the scales. Local land-use effects were related primarily to overall plant cover, and to the abundance and richness of flowering plants. Landscape effects, mostly limited to a 400 m range, were varied. The abundance of focal crop pollinators varied considerably between patch type and pollinator species. The different types of uncultivated habitats maintain complementary bee and flower communities. Our findings show the important role of uncultivated habitat patches in providing floral and nesting resources for bees, and creating resource-landscapes that can support wild bee communities and crop pollination services in Mediterranean agricultural landscapes. [ABSTRACT FROM AUTHOR]

Blueberry is one of the most relevant buzz‐pollinated crops worldwide and Chile is the most important global producer of fresh blueberries during wintertime in the Northern Hemisphere. Thousands of exotic Bombus terrestris are imported from Europe to pollinate blueberries. However, no study has investigated the performance of the native Chilean fauna to pollinate blueberry or other crops. Therefore, we aimed to compare the performance of native Chilean floral visitors with managed visitors to pollinate highbush blueberry.Per‐visit pollination performance (stigmatic pollen deposition) and floral visitation were measured and the presence of sonication behaviour of flower visitors was evaluated for five cultivars in two blueberry orchards located in southern Chile.Floral visitors showed a preference for one or more blueberry cultivars, instead of visiting all cultivars equally. Floral visits with sonication deposited more conspecific pollen on stigmas than visits without sonication. Some native sonicating bees (Cadeguala and Bombus), especially Cadeguala occidentalis, were efficient pollen vectors of blueberry and better pollinators than honeybees (5.8 times more pollen transferred) similar to that of the managed bee B. terrestris.The results indicate that some Chilean native bee species, especially those with sonication behaviour, can provide pollination service to highbush blueberry crops. [ABSTRACT FROM AUTHOR]

• Watermelon flowers attract diverse insect taxa but either honey bees or native bees are dominant in every region. • Honey bees and other bees are equally effective at pollen deposition on stigma. • Limited information located across major growing regions; majority of data is from North America. • Increasing bee density, encouraging wild taxa, and deploying land use practices will likely improve pollination. For most food crops the identity and efficiency of pollinators across key growing regions remains a significant knowledge gap that needs to be addressed before we can develop crop-specific approaches for pollination service delivery. Here, we conducted a systematic literature review and meta-analysis on watermelon (Citrullus lanatus (Thunb. Matsum. & Nakai)), a globally important fruit crop, to identify the floral visitors and their efficiency across different growing regions. We found that 265 insect species visit watermelon flowers (including 5 orders, 18 families and 75 genera) across 17 countries and 6 continents. Bees and flies were the most abundant flower visitors overall, but show distinct regional differences. Honey bees were the majority visitor in 53% of growing regions (range: 0 – 94%), whilst wild bee species were more abundant in 42% of regions (range: 3.4 – 100%). Honey bees and other bees were equally effective at depositing pollen on stigmas, but varied in effectiveness for fruit set and seed set. Pollination data from global studies appear to be limited for the largest-scale watermelon producers, namely: China, Turkey, and India, with the majority (56%) of data available from North America. This synthesis identified four key themes for improving pollination in watermelon: increasing honey bee densities on crops where local polices and environmental conditions are suitable; introducing other managed pollinators; identifying key wild pollinator taxa to encourage within crops; and improving local and landscape management practices to support pollinators. [ABSTRACT FROM AUTHOR]

Abstract Mason bees (Osmia spp.) are efficient fruit tree pollinators that can be encouraged to occupy and breed in artificial nesting material. In sweet cherry orchards, they are occasionally used as an alternative managed pollinator as a replacement for or in addition to honey bees (Apis mellifera). Yet, the lack of practical guidelines on management practices, for example optimal stocking rates, for both mason bee nesting material and honey bees might compromise pollination service provision. In this study, we assessed the relationship between stocking rates (honey bee hives and mason bee nesting material) and the abundance of honey bees and mason bees in 17 sweet cherry (Prunus avium) orchards in Central Germany. We furthermore performed a pollination experiment to explore the interactive effect of mason bees and honey bees on sweet cherry fruit set. In the orchards, both honey bee and mason bee abundance increased with increasing stocking rates of hives or nesting material, respectively. Honey bee abundance increased linearly with stocking rates. In contrast, mason bee abundance asymptoted at 2–3 nesting boxes per ha, beyond which more boxes resulted in little increase in visitation rate. Our pollination experiment demonstrated that orchards were pollen limited, with only 28% of insect‐pollinated flowers setting fruit versus 39% of optimally hand‐pollinated flowers. Honey bees and mason bees enhanced sweet cherry fruit set, but only when both were present and not when either was present alone in an orchard. Our findings demonstrate that offering nesting material for mason bees and employing honey bee hives can enhance bee abundance in sweet cherry orchards. By increasing honey bee abundance in combination with enhanced mason bee abundance, farmers can substantially boost fruit set and potentially sweet cherry yield. To enhance pollination services, farmers should consider the benefits of increasing pollinator biodiversity as an immediate benefit to improve crop yields.

Abstract Despite the importance of insect pollination to produce marketable fruits, insect pollination management is limited by insufficient knowledge about key crop pollinator species. This lack of knowledge is due in part to (1) the extensive labour involved in collecting direct observations of pollen transport, (2) the variability of insect assemblages over space and time and (3) the possibility that pollinators may need access to wild plants as well as crop floral resources. We address these problems using strawberry in the United Kingdom as a case study. First, we compare two proxies for estimating pollinator importance: flower visits and pollen transport. Pollen‐transport data might provide a closer approximation of pollination service, but visitation data are less time‐consuming to collect. Second, we identify insect parameters that are associated with high importance as pollinators, estimated using each of the proxies above. Third, we estimated insects' use of wild plants as well as the strawberry crop. Overall, pollinator importances estimated based on easier‐to‐collect visitation data were strongly correlated with importances estimated based on pollen loads. Both frameworks suggest that bees (Apis and Bombus) and hoverflies (Eristalis) are likely to be key pollinators of strawberries, although visitation data underestimate the importance of bees. Moving beyond species identities, abundant, relatively specialised insects with long active periods are likely to provide more pollination services. Most insects visiting strawberry plants also carried pollen from wild plants, suggesting that pollinators need diverse floral resources. Identifying essential pollinators or pollinator parameters based on visitation data will reach the same general conclusions as those using pollen transport data, at least in monoculture crop systems. Managers may be able to enhance pollination service by preserving habitats surrounding crop fields to complement pollinators' diets and provide habitats for diverse life stages of wild pollinators.

Pollination services provided by a diversity of pollinators are critical in agriculture because they enhance the yield of many crops. However, few studies have assessed pollination services in urban agricultural systems. We performed flower–visitor observations and pollination experiments on strawberries (Fragaria × ananassa) in an urban area near Paris, France, in order to assess the effects of (i) insect-mediated pollination service and (ii) potential pollination deficit on fruit set, seed set, and fruit quality (size, weight, and malformation). Flower–visitor observations revealed that the pollinator community solely comprised unmanaged pollinators, despite the presence of beehives in the surrounding landscape. Based on the pollination experiments, we found that the pollination service mediated by wild insects improved the fruit size as a qualitative value of production, but not the fruit set. We also found no evidence of pollination deficit in our urban environment. These results suggest that the local community of wild urban pollinators is able to support strawberry crop production and thus plays an important role in providing high-quality, local, and sustainable crops in urban areas.

IntroductionBees capable of performing floral sonication (or buzz-pollination) are among the most effective pollinators of blueberries. However, the quality of pollination provided varies greatly among species visiting the flowers. Consequently, the correct identification of flower visitors becomes indispensable to distinguishing the most efficient pollinators of blueberry. However, taxonomic identification normally depends on microscopic characteristics and the active participation of experts in the decision-making process. Moreover, the many species of bees (20,507 worldwide) and other insects are a challenge for a decreasing number of insect taxonomists. To overcome the limitations of traditional taxonomy, automatic classification systems of insects based on Machine-Learning (ML) have been raised for detecting and distinguishing a wide variety of bioacoustic signals, including bee buzzing sounds. Despite that, classical ML algorithms fed by spectrogram-type data only reached marginal performance for bee ID recognition. On the other hand, emerging systems from Deep Learning (DL), especially Convolutional Neural Networks (CNNs), have provided a substantial boost to classification performance in other audio domains, but have yet to be tested for acoustic bee species recognition tasks. Therefore, we aimed to automatically identify blueberry pollinating bee species based on characteristics of their buzzing sounds using DL algorithms.MethodsWe designed CNN models combined with Log Mel-Spectrogram representations and strong data augmentation and compared their performance at recognizing blueberry pollinating bee species with the current state-of-the-art models for automatic recognition of bee species.Results and DiscussionWe found that CNN models performed better at assigning bee buzzing sounds to their respective taxa than expected by chance. However, CNN models were highly dependent on acoustic data pre-training and data augmentation to outperform classical ML classifiers in recognizing bee buzzing sounds. Under these conditions, the CNN models could lead to automating the taxonomic recognition of flower-visiting bees of blueberry crops. However, there is still room to improve the performance of CNN models by focusing on recording samples for poorly represented bee species. Automatic acoustic recognition associated with the degree of efficiency of a bee species to pollinate a particular crop would result in a comprehensive and powerful tool for recognizing those that best pollinate and increase fruit yields.

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. [ABSTRACT FROM AUTHOR]

In the tropics, combining food security with biodiversity conservation remains a major challenge. Tropical agroforestry systems are among the most biodiversity‐friendly and productive land‐use systems, and 70% of cocoa is grown by >6 million smallholder farmers living on <2$ per day. In cacao's main centre of diversification, the western Amazon region, interest is growing to achieve premium prices with the conversion of high‐yielding, but mostly bulk‐quality cacao to native fine‐flavor cacao varieties, culturally important since pre‐Columbian times. Conversion to native cacao can be expected to favor adaptation to regional climate and growth conditions, and to enhance native biodiversity and ecosystem services such as biological pest control and pollination, but possibly also imply susceptibility to diseases. Experience from successful conversion of non‐native cacao plantations to fine‐flavor cacao agroforestry with rejuvenation by grafting and under medium‐canopy cover levels (30%–40%) can ensure a smooth transition with only minor temporary productivity gaps. This includes ongoing selection programs of high yielding and disease resistant native fine‐flavor cacao genotypes and organizing in cooperatives to buffer the high market volatility. In conclusion, the recent interest on converting bulk cacao to a diversity of native fine‐flavor varieties in countries like Peru is a challenge, but offers promising socio‐ecological perspectives. [ABSTRACT FROM AUTHOR]

An increasing number of farmland initiatives aim to aid biodiversity conservation through alternative farming practices such as nature-inclusive farming. However, these approaches frequently lead to trade-offs between biodiversity conservation and crop yield. For example, buckwheat (Fagopyrum esculentum) is a melliferous crop that flowers for a long period in the summer when nectar in agricultural areas is generally scarce, and buckwheat cultivation could therefore contribute to wild pollinator conservation. However, honeybees (Apis mellifera) are placed to ensure sufficient crop pollination, which potentially increases resource competition with wild pollinators in and around the crop. Here, we have studied this trade-off by surveying pollinators in and around 16 small-scale (∼1 ha) flowering buckwheat fields and we determined the contribution of pollinator density to crop yield in a nature-inclusive farming project. We found that the buckwheat pollinator community was diverse, albeit dominated by honeybees. We found no clear indications of resource competition between honeybees and wild pollinators within the buckwheat fields. Honeybee density in the surroundings was generally low, and increased minimally during honeybee-hive placement. While densities of honeybees decreased non-linearly over the day in buckwheat fields, they did not (temporarily) move into the surroundings of the field, suggesting limited competition for resources with wild pollinators. Crop yield was largely dependent on crop pollinator density, notably of honeybees, and to a lesser extent crop biomass (as a proxy for agricultural management). Our results show that buckwheat cultivation fits well within nature-inclusive farming if some simple precautionary measures are being taken, such as limiting the honeybee-hive densities and placing hives only during the main flowering period. The introduction of buckwheat cultivation into crop rotation could then contribute to fill an important nectar gap in the summer, which potentially boosts wild pollinator populations in the long term. [ABSTRACT FROM AUTHOR]

Supporting and promoting invertebrate diversity within agricultural ecosystems has numerous benefits, including the provision of pollination services. Many insects, including wild pollinators, require floral resources for food and structural habitat for nesting. To support pollinators, research studies and agri‐environment schemes have sought to supplement floral resources, but little is known about the value of different types of nesting habitat enhancements (e.g., trap‐nests or bee hotels). We deployed eight replicates of each of three types (bamboo reed, hardwood block and sand/cement brick) of trap‐nests at five orchards in two apple and cherry growing regions (Bilpin and Orange) in Australia. Both reed and hardwood block trap‐nests attracted a diverse array of invertebrates, such as ants, wasps, spiders and bees, including a cleptoparasitic bee species (Thyreus sp.) not previously recorded in the region. Interestingly, two taxa of native bees (Megachile [Megachile] and Megachile [Eutricharaea]) used the artificial nests and were also observed visiting apple crops. There were significantly more native bees using trap‐nests in Orange (n = 65), where orchards are surrounded by agricultural landscapes, than in Bilpin (n = 2), where orchards are surrounded by native forests. Our findings show that artificial nest enhancements are used by native bees, as well as other nontarget invertebrate taxa, some of which can be predators of bees (ants, wasps, and spiders). Nesting habitat augmentation thus has potential to be used as a conservation tool, especially in areas where nesting sites are limited. However, future studies should also consider measures to reduce colonization by non‐target taxa. [ABSTRACT FROM AUTHOR]

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Abstract In the tropics, combining food security with biodiversity conservation remains a major challenge. Tropical agroforestry systems are among the most biodiversity‐friendly and productive land‐use systems, and 70% of cocoa is grown by >6 million smallholder farmers living on

ABSTRACT The dependence of commercial crops on pollinators is closely related to their reproductive strategies and has direct impacts on production yields. Fruit production of Averrhoa carambola, the star fruit, is highly dependent on bee pollination. This distylous species may exhibit monomorphism associated with self-compatibility, a condition that may influence its degree of dependence on pollinators for fruit set. We evaluated the floral morphology and mating system of A. carambola and their relationships with pollinator dependence in an apparently pin-monomorphic orchard to address the following questions: Is the orchard indeed pin-monomorphic? Is the orchard self-compatible? Are pollination services sufficient to reach maximum productivity? Is fruit set related to the number of visits? We investigated floral morphometrics, mating system, and pollination following standard methods of plant reproduction research. The orchard exhibited pin-monomorphism and self-compatibility. Herkogamy strongly impaired spontaneous self-pollination, emphasizing the relevance of pollinators to crop yield. Considering that Apis mellifera was the only pollinator observed, and that the orchard showed pollen limitation, we recommend the implementation of pollinator management strategies. Additional studies will be needed to assess if the atypical distyly observed here occurs in other situations.

Climate change is expected to alter pressure from insect pests and the abundance and effectiveness of insect pollinators across diverse agriculture and forestry systems. In response to warming, insects are undergoing or are projected to undergo shifts in their geographic ranges, voltinism, abundance, and phenology. Drivers include direct effects on the focal insects and indirect effects mediated by their interactions with species at higher or lower trophic levels. These climate-driven effects are complex and variable, sometimes increasing pest pressure or reducing pollination and sometimes with opposite effects depending on climatic baseline conditions and the interplay of these drivers. This special collection includes several papers illustrative of these biological effects on pests and pollinators. In addition, in response to or anticipating climate change, producers are modifying production systems by introducing more or different crops into rotations or as cover crops or intercrops or changing crop varieties, with potentially substantial effects on associated insect communities, an aspect of climate change that is relatively understudied. This collection includes several papers illustrating these indirect production system-level effects. Together, biological and management-related effects on insects comprise the necessary scope for anticipating and responding to the effects of climate change on insects in agriculture and forest systems. [ABSTRACT FROM AUTHOR]

Recent declines in the health of honey bee colonies used for crop pollination pose a considerable threat to global food security. Foraging by honey bee workers represents the primary route of exposure to a plethora of toxins and pathogens known to affect bee health, but it remains unclear how foraging preferences impact colony-level patterns of stressor exposure. Resolving this knowledge gap is crucial for enhancing the health of honey bees and the agricultural systems that rely on them for pollination. To address this, we carried out a national-scale experiment encompassing 456 Canadian honey bee colonies to first characterize pollen foraging preferences in relation to major crops and then explore how foraging behavior influences patterns of stressor exposure. We used a metagenetic approach to quantify honey bee dietary breadth and found that bees display distinct foraging preferences that vary substantially relative to crop type and proximity, and the breadth of foraging interactions can be used to predict the abundance and diversity of stressors a colony is exposed to. Foraging on diverse plant communities was associated with increased exposure to pathogens, while the opposite was associated with increased exposure to xenobiotics. Our work provides the first large-scale empirical evidence that pollen foraging behavior plays an influential role in determining exposure to dichotomous stressor syndromes in honey bees., (© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.)