Social insect males are relatively understudied, but knowledge of their biology is increasingly important for conservation of declining groups. Bumblebees are important pollinators in temperate, sub-arctic, and Alpine regions, but many species are in decline across the globe. Agri-environment schemes have been designed to support female bumblebees, but free-living males may also need support. Male bumblebees have an energetically expensive lifestyle, and so understanding their foraging choices may provide a first step towards designing interventions to support them in the wild. Using a series of controlled laboratory choice experiments, we demonstrate that males prefer sugar concentrations of between 50 and 60% when under either simple (binary) or complex (octanary) choice conditions when presented with a broad range of sugar concentrations. When presented with concentrations within this preferred range, males exhibit a clear preference for sugar solutions of 56% w/w sucrose when solutions differ by 4%. These results suggest that males maximise their rate of energy intake, as predicted by theoretical models, rather than minimise their water consumption. In the future, male preferences for high sugar concentrations can be combined with knowledge of baseline nectar concentrations and flower phenology to maximise the value of conservation interventions for this neglected sex.

中文翻译：

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雄性大黄蜂的花蜜偏好

社会性昆虫雄性的研究相对较少，但对其生物学的了解对于保护衰落的群体越来越重要。大黄蜂是温带、亚北极和高山地区的重要传粉者，但全球许多物种正在减少。农业环境计划旨在支持雌性大黄蜂，但自由生活的雄性可能也需要支持。雄性大黄蜂的生活方式非常昂贵，因此了解它们的觅食选择可能是设计干预措施以在野外支持它们的第一步。使用一系列受控的实验室选择实验，我们证明在简单（二元）或复杂（八元）选择条件下，当呈现广泛的糖浓度时，男性更喜欢 50% 到 60% 的糖浓度。当以该优选范围内的浓度呈现时，当溶液相差 4% 时，雄性对 56% w/w 蔗糖的糖溶液表现出明显的偏好。这些结果表明，正如理论模型所预测的那样，男性会最大限度地吸收能量，而不是最大限度地减少水的消耗。未来，男性对高糖浓度的偏好可以与基线花蜜浓度和花卉物候学知识相结合，以最大限度地提高保护干预对这种被忽视的性别的价值。