Market forces influence helping behaviour in cooperatively breeding paper wasps

Biological market theory is potentially useful for understanding helping behaviour in animal societies. It predicts that competition for trading partners will affect the value of commodities exchanged. It has gained empirical support in cooperative breeders, where subordinates help dominant breeders in exchange for group membership, but so far without considering one crucial aspect: outside options. We find support for the existence of a biological market in paper wasps, Polistes dominula. We first show that females have a choice of cooperative partners. Second, by manipulating entire subpopulations in the field, we increased the supply of outside options for subordinates, freeing up suitable nesting spots and providing additional nesting partners. We predicted that by intensifying competition for help, our manipulation would force dominants to accept a lower price for group membership. As expected, subordinates reduced their foraging effort following our treatments. We conclude that to...

生物市场理论（biological market theory）为理解动物社会中的互助行为提供了颇具潜力的研究路径。该理论预测，对交易伙伴的竞争会影响交换交易品的价值。该理论已在合作繁育类群中获得实证支持：从属个体协助优势繁育者，以此换取群体成员资格，但现有研究尚未考虑一个关键维度——外部选择。我们在纸巢胡蜂（paper wasps，Polistes dominula）中验证了生物市场的存在性：首先证实雌性个体拥有选择合作伙伴的权利；其次，通过野外操控整个亚种群，我们提升了从属个体的外部选择供给量，释放了适宜筑巢位点并额外提供了筑巢伙伴。我们预测，该操控会加剧对协助行为的竞争，迫使优势个体为群体成员资格接受更低的交换代价。实验结果与预期一致，经处理后从属个体的觅食投入显著降低。综上，我们认为……