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双重维度的复杂性，是行为生态学领域的重要研究问题。当面临营养构成多样的资源，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自身觅食行程的难题，包括选择何种觅食资源、以及以何种顺序采集这些资源。本研究探讨了资源与需求的营养差异如何塑造熊蜂的觅食行程结构。熊蜂工蜂会为蜂群内具有不同营养需求的个体采集两种营养成分迥异的资源：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。本研究在实验室条件下饲养了东方熊蜂（Bombus impatiens）的蜂群，分别给予高蛋白日粮与蛋白限制日粮，并在设置了低、中、高三种花粉-花蜜比例的人工花朵上，评估熊蜂的觅食行程结构。本研究同时采用传统的花朵恒定度（floral constancy）指标与分层贝叶斯分析（hierarchical Bayesian analyses）方法，对觅食行程结构进行了分析。结果显示，来自花粉饱足蜂群的工蜂会响应花朵花粉-花蜜比例的变化，当花蜜供应量较高时，它们倾向于连续采集花粉。与之相反，来自蛋白限制蜂群的觅食者对花朵奖励比例相对不敏感，无论花蜜供应量如何，它们都倾向于长时间连续采集花粉。本研究最后讨论了上述发现对熊蜂为植物提供传粉服务的启示。