Bumblebees exposed to neonicotinoid pesticides collect less pollen on foraging trips. Exposed bumblebees are also slower to learn to handle flowers, which may account for reduced pollen collection. It is unclear, however, why neonicotinoid exposure slows learning to handle flowers. We investigated the effect of imidacloprid, a neonicotinoid pesticide, on bumblebee motor learning using a lab model of flower handling. Bumblebees learned to invert inside a narrow tube and lift a petal-shaped barrier to reach a reward chamber. Imidacloprid-exposed bumblebees showed a dose-dependent delay to solve the task, which resulted from reduced switching between behavioural strategies and a subsequent delay in use of the successful strategy. This effect was consistent in colonies exposed at 10 but not 2.6 ppb, suggesting a variable effect on individuals at lower doses. These results help to explain why exposed bumblebees are slow to learn to handle flowers and collect less pollen on foraging trips.

中文翻译：

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吡虫啉会影响大黄蜂（Bombus impatiens）的模型花处理任务的性能。

暴露于新烟碱类农药的大黄蜂在觅食旅行中收集的花粉较少。暴露的大黄蜂学习花的速度也较慢，这可能导致花粉减少。然而，尚不清楚为什么新烟碱暴露会减慢学习处理花的速度。我们使用花处理的实验室模型调查了新烟碱类农药吡虫啉对大黄蜂运动学习的影响。大黄蜂学会了在狭窄的试管内倒转并举起花瓣状的障碍物到达奖励室。吡虫啉暴露于吡虫啉的大黄蜂显示出解决任务的剂量依赖性延迟，这是由于减少了行为策略之间的切换以及随后使用成功策略的延迟。在暴露于10 ppb而不是2.6 ppb的菌落中，这种效果是一致的，提示在较低剂量下对个体的影响可变。这些结果有助于解释为什么裸露的大黄蜂在觅食旅行中学习花的速度慢并且收集的花粉少。