群居昆虫（蚂蚁、蜜蜂和黄蜂）并不像人们经常以为的那样是完全不育的，而是能产生它们自己的雄性后代。然而，此前人们不知道工蜂能够在其同一物种的其他群落中寄生生育后代。大黄蜂就能做到这一点。该发现表明，这种行为是非常普遍的，这也许可解释为什么关于亲缘选择的演化理论虽然在其他方面是成功的、但在解释天然蜂群中的工蜂生殖分布时却存在困难。
Social parasitism by male-producing reproductive workers in a eusocial insect
The evolution of extreme cooperation, as found in eusocial insects (those with a worker caste), is potentially undermined by selfish reproduction among group members. In some eusocial Hymenoptera (ants, bees and wasps), workers can produce male offspring from unfertilized eggs. Kin selection theory predicts levels of worker reproduction as a function of the relatedness structure of the workers' natal colony and the colony-level costs of worker reproduction. However, the theory has been only partially successful in explaining levels of worker reproduction. Here we show that workers of a eusocial bumble bee (Bombus terrestris) enter unrelated, conspecific colonies in which they then produce adult male offspring, and that such socially parasitic workers reproduce earlier and are significantly more reproductive and aggressive than resident workers that reproduce within their own colonies. Explaining levels of worker reproduction, and hence the potential of worker selfishness to undermine the evolution of cooperation, will therefore require more than simply a consideration of the kin-selected interests of resident workers. It will also require knowledge of the full set of reproductive options available to workers, including intraspecific social parasitism.
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