Field J, Foster W
Department of Biology, University College London
Anim Behav. 1999 Mar;57(3):633-636. doi: 10.1006/anbe.1999.0995.
A candidate explanation for the evolution of eusociality is that helpers are physiologically constrained such that helping is their only realistic option. We tested this subfertility hypothesis in a species of facultatively eusocial hover wasp (Hymenoptera, Stenogastrinae: Liostenogaster flavolineata) by seeing whether helpers that were forced to nest on their own were able to mature their own eggs. One focal helper was left alone on each of 22 nests, from which all other adult wasps (including the dominant) were permanently removed. After 18 days, all but one of the 19 focal helpers that remained on their nests had ovarian development and insemination status characteristic of dominants, and the majority had probably laid eggs. This was in striking contrast to the reproductive status of other helpers removed from the same nests at the start of the experiment. These results provide convincing experimental evidence that females do not become helpers because of some unconditional physiological constraint. There is currently no unequivocal support for the subfertility hypothesis in facultatively eusocial Hymenoptera lacking morphological castes. Copyright 1999 The Association for the Study of Animal Behaviour.
对真社会性进化的一种可能解释是，帮手在生理上受到限制，以至于帮助他人是他们唯一现实的选择。我们通过观察被迫独自筑巢的帮手是否能够使自己的卵成熟，在一种兼性真社会性悬巢黄蜂（膜翅目，狭腹胡蜂科：黄纹狭腹胡蜂）中对这种生育力低下假说进行了测试。在22个蜂巢中的每一个上单独留下一只作为重点观察的帮手，将所有其他成年黄蜂（包括占主导地位的黄蜂）永久性地移走。18天后，留在蜂巢上的19只重点观察的帮手中，除了一只之外，其他所有帮手都具有占主导地位黄蜂的卵巢发育和受精状态特征，并且大多数可能已经产卵。这与在实验开始时从同一蜂巢中移走的其他帮手的生殖状态形成了鲜明对比。这些结果提供了令人信服的实验证据，表明雌性不会因为某些无条件的生理限制而成为帮手。目前，在缺乏形态等级的兼性真社会性膜翅目中，对生育力低下假说没有明确的支持。版权所有1999动物行为研究协会。
