Data from: Combined exposure to sublethal concentrations of an insecticide and a fungicide affect feeding, ovary development and longevity in a solitary bee

Pollinators in agroecosystems are often exposed to pesticide mixtures. Even at low concentrations, the effects of these mixtures on bee populations are difficult to predict due to potential synergistic interactions. We orally exposed newly-emerged females of the solitary bee Osmia bicornis to environmentally-realistic levels of clothianidin (neonicotinoid insecticide) and propiconazole (fungicide), singly and in combination. The amount of feeding solution consumed was highest in bees exposed to the neonicotinoid, and lowest in bees exposed to the pesticide mixture. Ovary maturation and longevity of bees of the neonicotinoid and the fungicide treatments did not differ from those of control bees. In contrast, bees exposed to the pesticide mixture showed slow ovary maturation and decreased longevity. We found a synergistic interaction between the neonicotinoid and the fungicide on survival probability. We also found an interaction between treatment and emergence time (an indicator of physiological condition) on longevity. Longevity was negatively correlated to physiological condition only in the fungicide and the mixture treatments. Delayed ovary maturation and premature death imply a shortened nesting period (highly correlated to fecundity in Osmia). Our findings provide a mechanism to explain the observed dynamics of solitary bee populations exposed to multiple chemical residues in agricultural environments.农业生态系统中的传粉昆虫常暴露于复合农药环境中。即便处于低浓度水平，此类复合农药对蜂群的影响仍难以精准预测，原因在于其潜在的协同交互作用。我们采用符合环境实际暴露水平的噻虫胺（clothianidin，新烟碱类杀虫剂）与丙环唑（propiconazole，杀菌剂），通过经口暴露的方式，分别单独及联合处理新羽化的雌性独居蜂双角壁蜂（Osmia bicornis）。受试蜂的取食液摄入量在噻虫胺单独暴露组中最高，而在复合农药暴露组中最低。单独施加新烟碱类杀虫剂或杀菌剂处理的蜂群，其卵巢成熟程度与寿命均与对照组无显著差异。与之形成鲜明对比的是，复合农药暴露组的蜂群表现出卵巢成熟迟缓以及寿命缩短的表型。我们发现新烟碱类杀虫剂与杀菌剂之间存在对存活概率的协同交互效应。此外，我们还观察到处理方式与羽化时间（生理状态的指示指标）之间对寿命存在交互影响。仅在杀菌剂单独暴露组与复合农药暴露组中，蜂群寿命与生理状态呈负相关关系。卵巢成熟延迟与过早死亡意味着筑巢周期缩短，而筑巢周期与双角壁蜂的繁殖力高度相关。本研究结果为解释农业环境中暴露于多种化学残留的独居蜂种群动态提供了潜在机制。