Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, University of Sydney, Sydney, NSW, Australia.
J Evol Biol. 2014 May;27(5):939-49. doi: 10.1111/jeb.12366. Epub 2014 Apr 11.
Most societies are vulnerable to rogue individuals that pursue their own interests at the expense of the collective entity. Societies often protect themselves from selfish behaviour by 'policing', thereby enforcing the interests of the collective over those of individuals. In insect societies, for example, selfish workers can activate their ovaries and lay eggs, exploiting the collective brood rearing system for individual benefit. Policing, usually in the form of oophagy of worker-laid eggs, controls selfish behaviour. Importantly, once an effective system of policing has evolved, the incentive for personal reproduction is lost, and 'reproductive acquiescence' in which ovary activation is rare or absent is predicted to evolve. Studies of social Hymenoptera have largely supported the prediction of worker 'acquiescence'; workers of most species where policing is well developed have inactive ovaries. However, the eastern honeybee Apis cerana appears to be an exception. A. cerana colonies are characterized by highly efficient policing, yet about 5% of workers have active ovaries, even when a queen is present. This suggests that the evolution of acquiescence is incomplete in A. cerana. We regularly sampled male eggs and pupae from four A. cerana colonies. Workers had high levels of ovary activation overall (11.7%), and 3.8% of assignable male eggs and 1.1% of assignable male pupae were worker-laid. We conclude that workers with active ovaries lay their eggs, but these rarely survive to pupation because of intense policing. We then used our findings as well as previously published data on A. cerana and A. mellifera to redo the meta-analysis on which reproductive acquiescence theory is based. Including data on both species did not affect the relationship between effectiveness of policing and levels of worker reproduction. Their inclusion did, however, seriously weaken the relationship between relatedness among workers and levels of worker reproduction. Our work thus suggests that relatedness among workers does not affect the probability that workers will attempt to reproduce, but that it is coercion by peers that limits worker reproduction.
大多数社会都容易受到追求自身利益而损害集体实体的流氓个体的影响。社会通常通过“监管”来保护自己免受自私行为的侵害，从而将集体利益置于个人利益之上。例如，在昆虫社会中，自私的工蜂可以激活自己的卵巢并产卵，从而利用集体育雏系统为个人谋取利益。监管，通常以工蜂产卵的食卵行为的形式，控制自私行为。重要的是，一旦形成有效的监管系统，个人繁殖的动力就会丧失，并且预计会出现卵巢激活很少或不存在的“生殖默许”。对社会性膜翅目昆虫的研究在很大程度上支持了工蜂“默许”的预测；在监管完善的大多数物种中，工蜂的卵巢都不活跃。然而，东方蜜蜂 Apis cerana 似乎是个例外。A. cerana 群体以高效的监管为特征，但大约 5%的工蜂有活跃的卵巢，即使有蜂王存在也是如此。这表明在 A. cerana 中，默许的进化是不完全的。我们定期从四个 A. cerana 群体中取样雄性卵和蛹。工蜂的卵巢激活率总体较高（11.7%），可分配的雄性卵中有 3.8%和可分配的雄性蛹中有 1.1%是工蜂产卵。我们的结论是，有活跃卵巢的工蜂会产卵，但由于监管严格，这些卵很少能存活到蛹期。然后，我们利用我们的发现以及之前关于 A. cerana 和 A. mellifera 的数据，重新进行了基于生殖默许理论的荟萃分析。纳入这两个物种的数据并没有影响监管有效性与工蜂繁殖水平之间的关系。然而，纳入这些数据严重削弱了工蜂之间的亲缘关系与工蜂繁殖水平之间的关系。因此，我们的工作表明，工蜂之间的亲缘关系不会影响它们试图繁殖的概率，而是同伴的胁迫限制了工蜂的繁殖。
