With 2000 species currently recorded in Europe, bees are a highly diversified and efficient group of pollinating insects. Their decline could therefore lead to a risk for ecosystems functioning and crop yields. The drivers of this decline have been well documented in Europe and involve multiple factors such as pesticides, pathogens, poor nutrition, climate change, and their respective interactions. For pesticides, there is a lack of information concerning the impacts of exposure when the bees have access to pollen diet of different nutritional quality (e.g. variation in sterol and protein content). We performed bioassays on nine groups consisting of 10 Bombus terrestris microcolonies (i.e. queen less colonies) each in a fully crossed experiment including controls without pesticide, two different doses of neonicotinoid imidacloprid (2 and 20 μg/L) and three pollen diets (i.e. Salix mix, cellulose-diluted Salix mix and cellulose-diluted Salix mix enriched with soy protein). All colonies were fed ad libitum with syrup and pollen. We measured the collection of pollen and syrup, the brood mass and the pollen efficacy (ratio of brood mass/pollen) at the end of the experiment. All these variables were affected by the imidacloprid doses, especially pollen efficacy, which was two and 10 times lower than the control for the 2 and 20 μg/L treatments, respectively. As expected, pollen efficacy was also affected by the pollen diet. However, when exposed to imidacloprid, the three different pollen diets did not affect micro-colonies performances. Overall, we show that diet quality does not affect sensitivity to imidacloprid exposure. It seems therefore that the negative effects of imidacloprid exposure cannot be compensated for by a pollen diet of high quality.

蜜蜂目前在欧洲记录有2000种，是高度多样化和高效的授粉昆虫群。因此，它们的下降可能导致生态系统功能和农作物产量的风险。在欧洲，这种下降的驱动因素已得到充分证明，涉及多种因素，例如农药，病原体，营养不良，气候变化及其各自的相互作用。对于农药，当蜜蜂获得不同营养质量（例如，固醇和蛋白质含量的变化）的花粉饮食时，缺乏有关暴露影响的信息。我们对9个小组进行了生物测定，包括10个熊熊藜在完全交叉的实验中，每个微菌落（即少蚁后的菌落）均包括无农药的对照，两种不同剂量的新烟碱类吡虫啉（2和20μg/ L）和三种花粉饮食（即柳柳混合物，纤维素稀释柳柳混合物和纤维素稀浆）柳混合物富含大豆蛋白）。随意喂食所有菌落与糖浆和花粉。在实验结束时，我们测量了花粉和糖浆的收集，育雏量和花粉功效（育雏量/花粉的比率）。所有这些变量均受到吡虫啉剂量（特别是花粉功效）的影响，其剂量分别比2和20μg/ L处理的对照低2倍和10倍。不出所料，花粉饮食也影响花粉功效。然而，当暴露于吡虫啉时，三种不同的花粉饮食不影响微菌落的表现。总体而言，我们表明饮食质量不会影响对吡虫啉暴露的敏感性。因此，似乎吡虫啉暴露的负面影响无法通过高质量的花粉饮食来弥补。