Data from: Nutritional complexity and the structure of bee foraging bouts

How foragers cope with complexity in both needs and resources is a major question in behavioral ecology. When faced with nutritionally diverse resources, or when foraging for offspring with divergent nutritional needs, animals must meet the challenge of how to structure their foraging bouts, including what resources to forage for and in what order (how) to collect them. We investigated how nutritional variation in resources and requirements shapes the structure of bumble bee foraging bouts. Bumble bee workers collect 2 nutritionally distinct resources for consumers with different nutritional needs, floral nectar (largely carbohydrates) for their own needs and that of larvae, and pollen (largely protein) that is used primarily by larvae. We maintained colonies of the Eastern Bumble Bee (Bombus impatiens) in the laboratory on either protein-rich or protein-limited diets and assessed bees’ foraging bout structure on artificial flowers that offered low, medium, or high ratios of pollen to nectar. We analyzed bout structure using both traditional floral constancy metrics as well as hierarchical Bayesian analyses. Bees from pollen-satiated colonies responded to variation in floral pollen:nectar ratios, tending to collect pollen consecutively when nectar volumes were high. In contrast, foragers from pollen-limited colonies were relatively insensitive to floral reward ratio, tending to collect pollen in long runs regardless of nectar volume. We discuss the implications of these findings for the pollination services that bees provide plants.觅食者如何应对需求与资源的双重复杂性，是行为生态学领域的核心研究议题之一。当面对营养组成多样的资源，或是为营养需求存在差异的后代觅食时，动物必须解决如何规划其觅食回合（foraging bout）的难题，包括选择何种觅食资源以及按何种顺序完成采集。本研究探究了资源与需求的营养差异如何塑造熊蜂的觅食回合结构。熊蜂工蜂会为蜂群内不同营养需求的个体采集两种营养特性迥异的资源：花蜜（主要成分为碳水化合物）用于满足自身及幼虫的营养需求，花粉（主要成分为蛋白质）则主要用于饲喂幼虫。我们在实验室中饲养东方熊蜂（Eastern Bumble Bee，*Bombus impatiens*）的蜂群，分别为其提供高蛋白日粮与限蛋白日粮，并在设置了低、中、高三种花粉-花蜜比例的人工花卉上，评估熊蜂的觅食回合结构。本研究同时采用传统的花卉恒定度（floral constancy）指标与分层贝叶斯（hierarchical Bayesian）分析方法，对觅食回合结构进行量化解析。来自花粉充足蜂群的熊蜂会随花卉花粉-花蜜比例的变化调整行为：在花蜜供应量较高时，倾向于连续采集花粉。与之相对，来自花粉受限蜂群的觅食工蜂对花部报酬比例相对不敏感，无论花蜜供应量如何，均倾向于长时间连续采集花粉。本研究探讨了上述发现对熊蜂为植物提供传粉服务的相关启示。