In bumble bees (Bombus spp.), where workers within the same colony exhibit up to a tenfold difference in mass, labor is divided by body size. Current adaptive explanations for this important life history feature are unsatisfactory. Within the colony, what is the function of the smaller workers? Here, we report on the differential robustness to starvation of small and large worker bumble bees (Bombus impatiens); when nectar is scarce, small workers remain alive significantly longer than larger workers. The presence of small workers, and size variation in general, might act as insurance against times of nectar shortage. These data may provide a novel, adaptive explanation, independent of division of labor, for size polymorphism within the worker caste.

中文翻译：

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小型工蜂（Bombus impatiens）比它们的大蜜蜂更能抵抗饥饿

在熊蜂 (Bombus spp.) 中，同一蜂群内的工蜂的质量差异高达十倍，劳动量除以体型。目前对这一重要生活史特征的适应性解释并不令人满意。在殖民地内，较小的工人的功能是什么？在这里，我们报告了小型和大型工蜂（Bombus impatiens）对饥饿的不同鲁棒性；当花蜜稀缺时，小型工人比大型工人活得更久。小工人的存在和一般的大小变化可能是防止花蜜短缺时期的保险。这些数据可以为工人种姓内的体型多态性提供一种新的、适应性的解释，独立于劳动分工。