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Pesticides help produce food for humanity's growing population, yet they have negative impacts on the environment. Limiting these impacts, while maintaining food supply, is a crucial challenge for modern agriculture. Mitigation measures are actions taken by pesticide users, which modify the risk of the application to nontarget organisms, such as bees. Through these, the impacts of pesticides can be reduced, with minimal impacts on the efficacy of the pesticide. Here we collate the scientific evidence behind mitigation measures designed to reduce pesticide impacts on bees using a systematic review methodology. We included all publications which tested the effects of any pesticide mitigation measure (using a very loose definition) on bees, at any scale (from individual through to population level), so long as they presented evidence on the efficacy of the measure. We found 34 publications with direct evidence on the topic, covering a range of available mitigation measures. No currently used mitigation measures were thoroughly tested, and some entirely lacked empirical support, showing a weak evidence base for current recommendations and policy. We found mitigation measure research predominantly focuses on managed bees, potentially failing to protect wild bees. We also found that label-recommended mitigation measures, which are the mitigation measures most often applied, specifically are seldom tested empirically. Ultimately, we recommend that more, and stronger, scientific evidence is required to justify existing mitigation measures to help reduce the impacts of pesticides on bees while maintaining crop protection. [ABSTRACT FROM AUTHOR]

Prunus necrotic ringspot virus (PNRSV) and prune dwarf virus (PDV) are pollen-borne viruses of important stone fruit crops, including peaches, which can cause substantial yield loss. Although both horizontal and vertical (i.e., seed) transmission of both viruses occurs through pollen, the role of flower-visiting insects in their transmission is not well understood. Bees and thrips reportedly spread PNRSV and PDV in orchards and greenhouse studies; however, the field spread of PNRSV and PDV in peach orchards in the southeastern United States is not explored. We hypothesized that bees and thrips may facilitate virus spread by carrying virus-positive pollen. Our 2-yr survey results show that 75% of captured bees are carrying virus-positive pollen and moving across the orchard while a subsample of thrips were also found virus positive. Based on morphology, Bombus, Apis, Andrena, Eucera, and Habropoda are the predominant bee genera that were captured in peach orchards. Understanding the role of bees and thrips in the spread of PNRSV and PDV will enhance our understanding of pollen-borne virus ecology. [ABSTRACT FROM AUTHOR]

Hive design and apicultural processes have not been fundamentally changed since the design and commercialization of the Langstroth moveable frame hive in 1854. Colonies of Apis mellifera Linnaeus (Hymentoptera: Apidae) (the honey bee) maintain a brood nest temperature within the narrow range of 34.5–35.5°C, critical for brood development. Apis mellifera invest considerable energy to maintain hive homeostasis through behavioral modification of the hive environment. Human honey-harvesting processes and removal of the honey-filled comb (a source of thermal mass) have a detrimental impact on hive temperature that requires an increased investment of energy to rectify. This additional energy demand on the bees is a form of stress to the colony and diverts workers away from other essential tasks to that of environmental management. We investigated the thermal energy loss resulting from the removal and extraction of honey, the rate of thermal loss of an Australian standard Langstroth 10 frame hive, and the effect of honey and wax as a thermal mass in unoccupied bee hive. The results demonstrate that considerable energy expenditure would be required to rectify the hive thermal environment after honey harvesting or honeycomb frame addition. Honey provides thermal mass in the beehive, acting as a thermal buffer to external temperature change, which may mediate part of the thermal losses from the simplistic design of the Langstroth hive. Identification of these impacts in current apicultural practice and hive design allows for the improvement in the design of beehives and associated practices. These improvements may reduce stress to the bee colony, increasing colony efficiency for pollination and nectar foraging. [ABSTRACT FROM AUTHOR]

Buzz-pollinated plants require visitation from vibration producing bee species to elicit full pollen release. Several important food crops are buzz-pollinated including tomato, eggplant, kiwi, and blueberry. Although more than half of all bee species can buzz pollinate, the most commonly deployed supplemental pollinator, Apis mellifera L. (Hymenoptera: Apidae; honey bees), cannot produce vibrations to remove pollen. Here, we provide a list of buzz-pollinated food crops and discuss the extent to which they rely on pollination by vibration-producing bees. We then use the most commonly cultivated of these crops, the tomato, Solanum lycopersicum L. (Solanales: Solanaceae), as a case study to investigate the effect of different pollination treatments on aspects of fruit quality. Following a systematic review of the literature, we statistically analyzed 71 experiments from 24 studies across different geopolitical regions and conducted a meta-analysis on a subset of 21 of these experiments. Our results show that both supplemental pollination by buzz-pollinating bees and open pollination by assemblages of bees, which include buzz pollinators, significantly increase tomato fruit weight compared to a no-pollination control. In contrast, auxin treatment, artificial mechanical vibrations, or supplemental pollination by non-buzz-pollinating bees (including Apis spp.), do not significantly increase fruit weight. Finally, we compare strategies for providing bee pollination in tomato cultivation around the globe and highlight how using buzz-pollinating bees might improve tomato yield, particularly in some geographic regions. We conclude that employing native, wild buzz pollinators can deliver important economic benefits with reduced environmental risks and increased advantages for both developed and emerging economies. [ABSTRACT FROM AUTHOR]

Edible fruit plants of tropical forests are important for the subsistence of traditional communities. Understanding the most important pollinators related to fruit and seed production of these plants is a necessary step to protect their pollination service and assure the food security of these communities. However, there are many important knowledge gaps related to floral biology and pollination in megadiverse tropical rainforests, such as the Amazon Forest, due mainly to the high number of plant species. Our study aims to indicate the main pollinators of edible plants (mainly fruits) of the Amazon forest. For this, we adopted a threefold strategy: we built a list of edible plant species, determined the pollination syndrome of each species, and performed a review on the scientific literature searching for their pollinator/visitors. The list of plant species was determined from two specialized publications on Amazon fruit plants, totaling 188 species. The pollination syndrome was determined for 161 species. The syndromes most frequently found among the analyzed species were melittophily (bee pollination), which was found in 101 of the analyzed plant species (54%) and cantharophily (beetle pollination; 26 species; 14%). We also found 238 pollinator/visitor taxa quoted for 52 (28%) plant species in previous publications, with 124 taxa belonging to Apidae family (bees; 52%), mainly from Meliponini tribe (58 taxa; 47%). Knowledge about pollinators is an important step to help on preserving their ecosystem services and maintaining the productivity of fruit trees in the Amazon. [ABSTRACT FROM AUTHOR]

The conservation of bee populations for pollination in agricultural landscapes has attracted a lot of recent research interest, especially for crop industries undergoing expansion to meet increased production demands. In Canada, much growth has been occurring with commercial cranberry production, a field crop which is largely dependent on bee pollination. Wild bee pollinators could be negatively impacted by losses of natural habitat surrounding cranberry fields to accommodate increased production, but growers have little insight on how to manage their lands to maximize the presence of wild bees. Here, we described a 2-yr study where bee diversity and species composition were investigated to better understand the dynamic between natural habitat and cranberry fields. Bees were sampled using pan-traps and hand netting both within cranberry fields and in one of the three adjacent natural habitat types once a week during the crop flowering period. We found that bee community composition among cranberry fields did not differ based on the respective adjacent habitat type, but fields bordered by meadows were marginally less diverse than fields bordered by forest. As one would expect, field and natural habitat communities differed in terms of species composition and species richness. There was no evidence that one type of natural habitat was more favorable for the bees than another. Future agrobiodiversity studies should simultaneously examine bee diversity comprised in both crop fields and adjacent natural environments to better understand the species dynamics essential to the preservation of pollination services. [ABSTRACT FROM AUTHOR]

Natural enemies and pollinators require nutritional and habitat resources that are often not found in conventional agricultural fields. The addition of flowering plants within agroecosystems may provide the resources necessary to support beneficial insects at the local scale. We hypothesized that insect pollinator and natural enemy abundance would increase in cucumber (Cucumis sativus) plots containing flower strips and that the effect would be greatest in the crop rows closest to the flower strips. Three flower treatments were tested: 1) buckwheat (Fagopyrum esculentum), 2) yellow mustard (Brassica hirta), 3) sweet alyssum (Lobularia maritima), and cucumbers as a control. Flowers were planted within a commercial cucumber field in 20-m-long strips in a randomized complete block design with six replications in the 2014 and 2015 growing seasons. Some floral treatments successfully attracted more beneficial insects than others, but the beneficials did not disperse out to the cucumber plants. Cucumber yield was unaffected by flowers with one exception: in 2015, cucumber yield in the sweet alyssum plots were greater than those in plots with no flowers. Our research indicates that adding flowers to cucumber fields to increase services from beneficial insects needs to be further investigated to better understand the effect of factors such as relative flowering strip size. [ABSTRACT FROM AUTHOR]

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