Kin-selection versus costs of inbreeding in the transition from subsocial to social spiders

蜘蛛的社会性已经独立进化了大约12次，然而，导致只有不到25个社会性物种。群居蜘蛛在几个方面与群居昆虫有明显的不同，例如，群居蜘蛛总是以极端近亲繁殖为特征。近亲交配确实会导致高度的亲缘关系，而社会性的演变需要亲属之间的联系，因为相关的个人更有可能合作。然而，近亲交配也与几个缺点有关，因此通常是避免的。因此，近亲繁殖一方面可以促进合作，而相关的适应成本将决定对近亲繁殖的容忍程度，并最终影响社会进化的潜力。这项研究的目的是确定导致群居蜘蛛极端近亲交配进化的选择压力和先决条件。我们将特别关注亲属选择和通过女性选择、一夫多妻制和性冲突对近亲交配的可能性有利或不利的性选择的具体作用。为了评估遗传多样性和遗传距离与合作进化和群体表现的相关性，我们将进行实验，测试从亲缘选择强烈有利于近亲繁殖的假设中得出的特定预测，在共同任务的进化中，如在这些蜘蛛中觅食。利用实验和分子遗传学，我们将评估自然种群中多次交配的作用及其对个体雌性适应能力的影响。具有三个独立进化的社会物种的剑鱼属是解决这些问题的理想物种。这项拟议的研究是基于先前对亚社会Stegodyphus lineatus蜘蛛的研究，这些研究发现：(1)对近亲交配有很高的耐受性，(2)亲缘关系对集体觅食和生长具有优势。另一项研究表明，多重亲子关系对年轻群体的短期不利影响。

Sociality has evolved about 12 times independently in spiders, however resulting in less than 25 social species. Social spiders differ markedly from the eusocial insects in several aspects, for example are social spiders always characterised by extreme inbreeding. Inbreeding does result in very high degrees of relatedness and the evolution of sociality requires kin-associations since related individuals are much more likely to cooperate. However, inbreeding is also associated with several disadvantages and is therefore usually avoided. Hence, inbreeding may on one side facilitate cooperation while the associated fitness costs will determine the level of tolerance towards inbreeding and ultimately influence the potential for social evolution. The aim of this study is to identify the selection pressures and preconditions that have led to the evolution of extreme inbreeding in social spiders. In particular, we will focus on kin selection and the specific role of sexual selection through female choice, polyandry and sexual conflict in favouring or disfavouring the likelihood of inbreeding. To assess the relevance of genetic diversity and genetic distance for the evolution of cooperation and group performance, we will conduct experiments that test specific predictions derived from the hypothesis that kin selection strongly favours inbreeding in the evolution of communal tasks such as foraging in these spiders. Using experiments and molecular genetics we will assess the role of multiple mating in natural populations and its consequences for individual female fitness. The genus Stegodyphus with three independently evolved social species is ideal to address these questions. The proposed research is based on previous studies of subsocial Stegodyphus lineatus spiders that found (1) a high tolerance towards inbreeding and (2) an advantage of relatedness for communal feeding and growth. An additional study suggested short-time disadvantages of multiple paternity for groups of young.