Delayed dispersal and prolonged brood care in a family-living beetle

Delayed juvenile dispersal is an important prerequisite for the evolution of family-based social systems, such as cooperative breeding and eusociality. In general, young adults forego dispersal if there are substantial benefits to remaining in the natal nest and/or the likelihood of dispersing and breeding successfully is low. We investigate some general factors thought to drive delayed juvenile dispersal in the horned passalus beetle, a family-living beetle in which young adults remain with their families in their natal nest for several months before dispersing. Fine scale population genetic structure indicated high gene flow between nest sites, suggesting that constraints on mobility are unlikely to explain philopatry. Young adults do not breed in their natal log and likely disperse before reaching breeding age, suggesting that they do not gain direct reproductive benefits from delayed dispersal. We also examined several ways in which parents might incentivize delayed dispersal by pro...

延迟幼体扩散是合作繁育（cooperative breeding）与真社会性（eusociality）等家族式社会系统演化的重要前提。一般而言，若留在出生巢中可获得显著收益，或扩散后成功繁殖的概率较低，年轻成虫便会放弃扩散。本研究以带角蜣螂（horned passalus beetle）为研究对象，该物种为具有家族群居特性的甲虫，其年轻成虫会在扩散前与家族一同留在出生巢内长达数月，旨在剖析驱动该物种幼体延迟扩散的若干通用影响因素。种群遗传结构的精细尺度分析显示，各巢位间存在较高的基因流，这表明移动性限制不大可能解释其恋巢性（philopatry）。年轻成虫并不会在出生的朽木中繁殖，且大概率会在达到繁殖年龄前完成扩散，这说明延迟扩散并未使它们获得直接的繁殖收益。我们还考察了亲代可能通过pro……以激励子代延迟扩散的多种途径。