The honey bee Apis mellifera, the test species used in the current environmental risk assessment procedure, is generally considered as extremely sensitive to pesticides when compared to other bee species, although a quantitative approach for comparing the difference in sensitivity among bees has not yet been reported. A systematic review of the relevant literature on the topic followed by a meta-analysis has been performed. Both the contact and oral acute LD50 and the chronic LC50 reported in laboratory studies for as many substances as possible have been extracted from the papers in order to compare the sensitivity to pesticides of honey bees and other bee species (Apiformes). The sensitivity ratio R between the endpoint for the species a (A. mellifera) and the species s (bees other than A. mellifera) was calculated for a total of 150 case studies including 19 bee species. A ratio higher than 1 indicated that the species s was more sensitive to pesticides than honey bees. The meta-analysis showed a high variability of sensitivity among bee species (R from 0.001 to 2085.7), however, in approximately 95 % of the cases the sensitivity ratio was below 10. The effect of pesticides in domestic and wild bees is dependent on the intrinsic sensitivity of single bee species as well as their specific life cycle, nesting activity and foraging behaviour. Current data indicates a need for more comparative information between honey bees and non-Apis bees as well as separate pesticide risk assessment procedures for non-Apis bees.

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Our results underscore the importance to test pesticide combinations likely to occur in agricultural environments, and to include several bee species in environmental risk assessment schemes. © 2016 Society of Chemical Industry.

The honey bee is a major pollinator whose health is of global concern. Declines in bee health are related to multiple factors, including resource quality and pesticide contamination. Intensive agricultural areas with crop monocultures potentially reduce the quality and quantity of available nutrients and expose bee foragers to pesticides. However, there is, to date, no evidence for synergistic effects between pesticides and nutritional stress in animals. The neonicotinoids clothianidin (CLO) and thiamethoxam (TMX) are common systemic pesticides that are used worldwide and found in nectar and pollen. We therefore tested if nutritional stress (limited access to nectar and access to nectar with low-sugar concentrations) and sublethal, field-realistic acute exposures to two neonicotinoids (CLO and TMX at 1/5 and 1/25 of LD 50 ) could alter bee survival, food consumption and haemolymph sugar levels. Bee survival was synergistically reduced by the combination of poor nutrition and pesticide exposure (−50%). Nutritional and pesticide stressors reduced also food consumption (−48%) and haemolymph levels of glucose (−60%) and trehalose (−27%). Our results provide the first demonstration that field-realistic nutritional stress and pesticide exposure can synergistically interact and cause significant harm to animal survival. These findings have implications for current pesticide risk assessment and pollinator protection.