Laboratoire d'Ethologie Expérimentale et Comparée E.A. 4443, Université Paris 13, , Sorbonne Paris Cité, Villetaneuse 93430, France, Departamento de Biologia, FFCLRP, Universidade de São Paulo (USP), , Ribeirão Preto, São Paulo, Brazil.
Proc Biol Sci. 2013 Sep 25;280(1771):20131888. doi: 10.1098/rspb.2013.1888. Print 2013 Nov 22.
Restricted reproduction is traditionally posited as the defining feature of eusocial insect workers. The discovery of worker reproduction in foreign colonies challenges this view and suggests that workers' potential to pursue selfish interests may be higher than previously believed. However, whether such reproductive behaviour truly relies on a reproductive decision is still unknown. Workers' reproductive decisions thus need to be investigated to assess the extent of workers' reproductive options. Here, we show in the bumblebee Bombus terrestris that drifting is a distinct strategy by which fertile workers circumvent competition in their nest and reproduce in foreign colonies. By monitoring workers' movements between colonies, we show that drifting is a remarkably dynamic behaviour, widely expressed by both fertile and infertile workers. We demonstrate that a high fertility is, however, central in determining the propensity of workers to enter foreign colonies as well as their subsequent reproduction in host colonies. Moreover, our study shows that the drifting of fertile workers reflects complex decision-making processes associated with in-nest reproductive competition. This novel finding therefore adds to our modern conception of cooperation by showing the previously overlooked importance of alternative strategies which enable workers to assert their reproductive interests.
传统上认为，生殖限制是真社会性昆虫工蜂的定义特征。在外国殖民地发现工蜂的繁殖能力挑战了这一观点，并表明工蜂追求自身利益的潜力可能比以前认为的要高。然而，这种生殖行为是否真的依赖于生殖决策尚不清楚。因此，需要研究工蜂的生殖决策，以评估工蜂生殖选择的程度。在这里，我们在熊蜂 Bombus terrestris 中表明，漂移是一种独特的策略，通过这种策略，有生育能力的工蜂可以在巢中规避竞争，并在外国殖民地繁殖。通过监测工蜂在殖民地之间的移动，我们表明漂移是一种非常活跃的行为，有生育能力和无生育能力的工蜂都广泛表现出这种行为。我们证明，高生育率是决定工蜂进入外国殖民地以及随后在宿主殖民地繁殖的倾向的核心因素。此外，我们的研究表明，有生育能力的工蜂的漂移反映了与巢内生殖竞争相关的复杂决策过程。因此，这一新颖的发现增加了我们对合作的现代概念，表明了以前被忽视的、能够使工蜂维护其生殖利益的替代策略的重要性。
