Schneider J M, Bilde T
Biozentrum Grindel, University of Hamburg, Martin-Luther-King Platz 3, D-20146 Hamburg, Germany.
Proc Natl Acad Sci U S A. 2008 Aug 5;105(31):10843-6. doi: 10.1073/pnas.0804126105. Epub 2008 Jul 25.
Interaction within groups exploiting a common resource may be prone to cheating by selfish actions that result in disadvantages for all members of the group, including the selfish individuals. Kin selection is one mechanism by which such dilemmas can be resolved. This is because selfish acts toward relatives include the cost of lowering indirect fitness benefits that could otherwise be achieved through the propagation of shared genes. Kin selection theory has been proved to be of general importance for the origin of cooperative behaviors, but other driving forces, such as direct fitness benefits, can also promote helping behavior in many cooperatively breeding taxa. Investigating transitional systems is therefore particularly suitable for understanding the influence of kin selection on the initial spread of cooperative behaviors. Here we investigated the role of kinship in cooperative feeding. We used a cross-fostering design to control for genetic relatedness and group membership. Our study animal was the periodic social spider Stegodyphus lineatus, a transitional species that belongs to a genus containing both permanent social and periodic social species. In S. lineatus, the young cooperate in prey capture and feed communally. We provide clear experimental evidence for net benefits of cooperating with kin. Genetic relatedness within groups and not association with familiar individuals directly improved feeding efficiency and growth rates, demonstrating a positive effect of kin cooperation. Hence, in communally feeding spiders, nepotism favors group retention and reduces the conflict between selfish interests and the interests of the group.
在利用共同资源的群体内部，互动可能容易受到自私行为的欺骗，这些行为会给群体的所有成员，包括自私的个体，带来不利影响。亲缘选择是解决此类困境的一种机制。这是因为对亲属的自私行为包括降低间接适合度收益的代价，而这种收益原本可以通过共享基因的传播来实现。亲缘选择理论已被证明对合作行为的起源具有普遍重要性，但其他驱动力，如直接适合度收益，在许多合作繁殖的分类群中也能促进帮助行为。因此，研究过渡系统特别适合于理解亲缘选择对合作行为初始传播的影响。在这里，我们研究了亲缘关系在合作觅食中的作用。我们采用交叉寄养设计来控制遗传相关性和群体成员身份。我们的研究对象是周期性社会蜘蛛细纹棘腹蛛，它是一个过渡物种，属于一个既包含永久性社会物种又包含周期性社会物种的属。在细纹棘腹蛛中，幼蛛在捕食时会合作并共同进食。我们为与亲属合作的净收益提供了明确的实验证据。群体内部的遗传相关性而非与熟悉个体的关联直接提高了觅食效率和生长速度，证明了亲缘合作的积极作用。因此，在共同进食的蜘蛛中，裙带关系有利于群体的维持，并减少了自私利益与群体利益之间的冲突。
