Division of Biological Sciences, Section of Ecology, Behavior, and Evolution, University of California, San Diego, 9500 Gilman Drive, MC0116, La Jolla, CA 92093-0116, USA
Department of Agricultural Sciences, Alma Mater Studiorum, University of Bologna, Viale Fanin 42, 40127 Bologna, Italy.
Proc Biol Sci. 2017 Dec 20;284(1869). doi: 10.1098/rspb.2017.1711.
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) 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.
蜜蜂是一种主要的传粉媒介，其健康状况受到全球关注。蜜蜂健康的下降与多种因素有关，包括资源质量和农药污染。在以农作物单一种植为主的集约农业区，可用营养物质的质量和数量可能会减少，同时使蜜蜂觅食者接触到农药。然而，迄今为止，还没有证据表明动物同时受到营养压力和农药的协同影响。新烟碱类杀虫剂噻虫嗪（TMX）和噻虫胺（CLO）是在世界范围内广泛使用的常见系统性杀虫剂，存在于花蜜和花粉中。因此，我们测试了营养压力（花蜜供应有限，以及接触低浓度含糖花蜜）和亚致死、田间实际急性暴露于两种新烟碱类杀虫剂（CLO 和 TMX，暴露浓度分别为 LD 的 1/5 和 1/25）是否会改变蜜蜂的存活率、食物消耗和血淋巴中糖的水平。不良营养和农药暴露的组合使蜜蜂的存活率协同降低了 50%。营养和农药应激源还降低了食物消耗（48%）和血淋巴中葡萄糖（60%）和海藻糖（27%）的水平。我们的研究结果首次证明了田间实际的营养压力和农药暴露可以协同作用，并对动物的生存造成显著危害。这些发现对当前的农药风险评估和传粉媒介保护具有重要意义。
