Russell A F, Young A J, Spong G, Jordan N R, Clutton-Brock T H
Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
Proc Biol Sci. 2007 Feb 22;274(1609):513-20. doi: 10.1098/rspb.2006.3698.
In both animal and human societies, individuals may forego personal reproduction and provide care to the offspring of others. Studies aimed at investigating the adaptive nature of such cooperative breeding systems in vertebrates typically calculate helper 'fitness' from relationships of helper numbers and offspring survival to independence. The aim of this study is to use observations and supplemental feeding experiments in cooperatively breeding meerkats, Suricata suricatta, to investigate whether helpers influence the long-term reproductive potential of offspring during adulthood. We show that helpers have a significant and positive influence on the probability that offspring gain direct reproductive success in their lifetimes. This effect arises because helpers both reduce the age at which offspring begin to reproduce as subordinates and increase the probability that they will compete successfully for alpha rank. Supplemental feeding experiments confirm the causality of these results. Our results suggest that one can neither discount the significance of helper effects when none is found nor necessarily estimate accurately the fitness benefit that helpers accrue, unless their effects on offspring are considered in the long term.
在动物和人类社会中，个体可能会放弃自身繁殖，而去照顾其他个体的后代。旨在研究脊椎动物这种合作繁殖系统适应性本质的研究，通常根据帮手数量与后代存活至独立的关系来计算帮手的“适合度”。本研究的目的是利用对合作繁殖的狐獴（Suricata suricatta）的观察和补充喂养实验，来探究帮手是否会影响后代成年后的长期繁殖潜力。我们发现，帮手对后代在其一生中获得直接繁殖成功的概率有显著的积极影响。这种影响的产生是因为帮手既降低了后代作为从属者开始繁殖的年龄，又增加了它们成功竞争到首领地位的概率。补充喂养实验证实了这些结果的因果关系。我们的结果表明，在未发现帮手效应时，不能忽视其重要性；而且，除非从长期角度考虑它们对后代的影响，否则不一定能准确估计帮手所获得的适合度益处。
