Consequences of a nectar yeast for pollinator preference and performance

Pollinators utilize floral resources that vary in colour, scent and reward quality. Variation in such traits, including nectar rewards, in addition to cues associated with their quality, can influence pollinator foraging decisions with consequences for pollinator reproductive success. Nectar is commonly subject to colonization by micro-organisms capable of affecting a suite of traits important for pollinator attraction and fitness; yet, links between microbial presence and changes in pollinator preference and performance remain few. Here, we evaluated the effects of a nectar-inhabiting micro-organism on pollinator foraging behaviour and reproduction using the common eastern bumblebee Bombus impatiens and the cosmopolitan nectar yeast Metschnikowia reukaufii. Using a combination of choice and no-choice behavioural and feeding assays, we manipulated the presence and viability of M. reukaufii in nectar and assessed bumblebee foraging and reproductive responses. Bombus impatiens workers r...传粉昆虫（pollinator）会利用色彩、气味与回报质量存在差异的花卉资源。此类性状（包括花蜜回报（nectar rewards））的变异，以及与其质量相关的信号，均可影响传粉昆虫的觅食决策（foraging decisions），进而对其繁殖成功率（reproductive success）产生影响。 花蜜通常会被微生物（micro-organism）定植，这些微生物能够改变一系列对传粉昆虫吸引度和适合度（fitness）至关重要的性状；然而，目前关于微生物存在与传粉昆虫偏好性及行为表现变化之间的关联研究仍较为匮乏。 本研究以普通东部熊蜂（Bombus impatiens）与广布花蜜酵母（Metschnikowia reukaufii）为实验材料，探究了花蜜栖居微生物对传粉昆虫觅食行为与繁殖的影响。 本研究结合选择实验（choice assay）与非选择实验（no-choice assay）及摄食测定（feeding assay）方法，操控了花蜜中该酵母的存在与否与活性（viability）状态，并评估了熊蜂的觅食与繁殖响应。 普通东部熊蜂工蜂（Bombus impatiens workers r...）