School of Marine Biology and Aquaculture, James Cook University, , Townsville, Queensland 4811, Australia.
Proc Biol Sci. 2010 Feb 7;277(1680):353-8. doi: 10.1098/rspb.2009.1453. Epub 2009 Oct 14.
Why non-breeding subordinates of many animal societies tolerate group-living remains a pertinent question in evolutionary biology. The ecological constraints and benefits of philopatry hypotheses have the potential to explain the maintenance of group-living by specifying the ecological conditions favouring delayed dispersal over independent breeding by subordinates. In this study, I used field and laboratory experiments to investigate the role of ecological and social factors on the dispersal decisions of non-breeding subordinates in the coral-dwelling fish, Paragobiodon xanthosomus (Gobiidae). Subordinate dispersal was strongly influenced by ecological constraints (habitat saturation and risks of movement) and benefits of philopatry (relative coral size). Social factors, namely social rank and forcible eviction, did not affect the occurrence of subordinate dispersal. These results suggest that selection has favoured subordinate P. xanthosomus, which employ a mixed strategy-switching tactics in response to three ecological factors-despite having low mobility and extreme habitat-specific requirements. Furthermore, this study demonstrates the generality of the ecological constraints and benefits of philopatry hypotheses as explanations for group-living in species where subordinates are unrelated to breeders, provide no help and do not strictly delay dispersal.
为什么许多动物社会的非繁殖下属会容忍群体生活，这在进化生物学中仍然是一个悬而未决的问题。亲代定居假说的生态约束和好处有可能通过指定有利于下属延迟扩散而不是独立繁殖的生态条件来解释群体生活的维持。在这项研究中，我使用野外和实验室实验来研究生态和社会因素对非繁殖下属在珊瑚鱼 Paragobiodon xanthosomus（Gobiidae）中的扩散决策的作用。下属的扩散受到生态约束（栖息地饱和和运动风险）和亲代定居的好处（相对珊瑚大小）的强烈影响。社会因素，即社会等级和强制驱逐，并不影响下属的扩散发生。这些结果表明，选择有利于采用混合策略转换策略的 P. xanthosomus 下属，以应对三个生态因素——尽管它们的流动性低且对特定栖息地的要求极高。此外，这项研究表明，亲代定居假说的生态约束和好处作为解释在非繁殖下属与繁殖者无关、不提供帮助且不严格延迟扩散的物种中群体生活的一般性解释。
