Climate change poses a threat to global food security with extreme heat events causing drought and direct damage to crop plants. However, by altering behavioural or physiological responses of insects, extreme heat events may also affect pollination services on which many crops are dependent. Such effects may potentially be exacerbated by other environmental stresses, such as exposure to widely used agro-chemicals. To determine whether environmental stressors interact to affect pollination services, we carried out field cage experiments on the buff-tailed bumble bee (Bombus terrestris). Using a Bayesian approach, we assessed whether heat stress (colonies maintained at an ambient temperature of 25 °C or 31 °C) and insecticide exposure (5 ng g^-1 of the neonicotinoid insecticide clothianidin) could induce behavioural changes that affected pollination of faba bean (Vicia faba). Only the bumble bee colonies and not the plants were exposed to the environmental stress treatments. Bean plants exposed to heat-stressed bumble bee colonies (31 °C) had a lower proportional pod set compared to colonies maintained at 25 °C. There was also weak evidence that heat stressed colonies caused lower total bean weight. Bee exposure to clothianidin was found to have no clear effect on plant yields, either individually or as part of an interaction. We identified no effect of either colony stressor on bumble bee foraging behaviours. Our results suggest that extreme heat stress at the colony level may impact on pollination services. However, as the effect for other key yield parameters was weaker (e.g. bean yields), our results are not conclusive. Overall, our study highlights the need for further research on how environmental stress affects behavioural interactions in plant-pollinator systems that could impact on crop yields.

中文翻译：

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大黄蜂授粉服务中菌落水平胁迫影响的模棱两可证据

气候变化对全球粮食安全构成威胁，极端高温事件导致干旱并直接损害农作物。但是，通过改变昆虫的行为或生理反应，极端高温事件也可能影响许多作物所依赖的授粉服务。其他环境压力（如接触广泛使用的农药）可能会加剧这种影响。为了确定环境压力源是否相互作用以影响授粉服务，我们对田尾大黄蜂（Bombus terrestris）进行了笼养实验。使用贝叶斯方法，我们评估了热应激（菌落保持在25°C或31°C的环境温度下）和杀虫剂暴露量（5 ng g ^-1新烟碱类杀虫剂可比安定的使用会诱导行为变化，从而影响蚕豆的授粉（野豌豆）。仅大黄蜂菌落而不是植物暴露于环境胁迫处理。与保持在25°C的菌落相比，暴露于热胁迫的大黄蜂菌落（31°C）的豆类植物的豆荚比例更低。也没有证据表明高温胁迫的菌落导致豆总重量降低。发现蜜蜂单独或作为相互作用的一部分，暴露于可比尼丁对植物产量没有明显影响。我们没有发现任何殖民地压力对大黄蜂觅食行为的影响。我们的结果表明，菌落水平的极端高温胁迫可能会影响授粉服务。但是，由于其他关键产量参数的影响较弱（例如豆类产量），因此我们的结果尚无定论。总体，