How a generalist bee achieves high efficiency of pollen collection on diverse floral resources

Bees foraging for floral rewards are one of our most thoroughly studied examples of generalist foraging ecology. Generalist bees rely considerably on instrumental (associative) learning to acquire routines that allow them to collect nectar efficiently from diverse plant species. Although such bees must also collect pollen from diverse species, few studies have examined if and how high efficiency is achieved. We characterized how generalist bumble bees (Bombus impatiens) foraged effectively for pollen from diverse floral resources, by manipulating the presence of pollen and anther cues, in a series of experiments using pollen-bearing live flowers, flowers of a sterile pollenless horticultural hybrid, and artificial flowers. We show that generalist bumble bees exhibit flexible and effective pollen collection by switching between 2 routines: “scrabbling” when pollen is abundant and “sonicating” when pollen is scarce. Efficient switching between these behaviors is regulated by the interplay...采集花报酬的蜜蜂是广谱觅食生态学（generalist foraging ecology）中被研究得最为深入的类群之一。广谱访花蜜蜂（generalist bees）很大程度上依赖工具性（联想）学习（instrumental (associative) learning）来习得行为程式，从而高效地从多种植物类群中采集花蜜。尽管这类蜜蜂同样需要从不同植物物种处采集花粉，但鲜有研究探讨其高效采粉行为是否存在及实现机制。本研究通过操控花粉与花药线索（anther cues）的有无，结合采用带粉活体花朵、不育无粉园艺杂交品种花朵及人工花朵的系列实验，解析了广谱访花熊蜂（Bombus impatiens）如何高效地从多样花源中采集花粉。我们发现，广谱访花熊蜂可通过切换两种行为程式实现灵活高效的花粉采集：当花粉充足时采用“刮擦（scrabbling）”行为，花粉匮乏时则采用“振蜂采粉（sonicating）”行为。这些行为间的高效切换受到相互作用的调控……