Johannesen Jes, Lubin Yael, Smith Deborah R, Bilde Trine, Schneider Jutta M
Institut für Zoologie, Abteilung Okologie, Universität Mainz, Saarstrasse 21, 55099 Mainz, Germany.
Proc Biol Sci. 2007 Jan 22;274(1607):231-7. doi: 10.1098/rspb.2006.3699.
Social, cooperative breeding behaviour is rare in spiders and generally characterized by inbreeding, skewed sex ratios and high rates of colony turnover, processes that when combined may reduce genetic variation and lower individual fitness quickly. On these grounds, social spider species have been suggested to be unstable in evolutionary time, and hence sociality a rare phenomenon in spiders. Based on a partial molecular phylogeny of the genus Stegodyphus, we address the hypothesis that social spiders in this genus are evolutionary transient. We estimate the age of the three social species, test whether they represent an ancestral or derived state and assess diversification relative to subsocial congeners. Intraspecific sequence divergence was high in all of the social species, lending no support for the idea that they are young, transient species. The age of the social lineages, constant lineage branching and the likelihood that social species are independently derived suggest that either the social species are 'caught in sociality' or they have evolved into cryptic species.
社会性合作繁殖行为在蜘蛛中很罕见，通常表现为近亲繁殖、性别比例失衡和群体更替率高，这些过程结合起来可能会迅速降低遗传变异并降低个体适应性。基于这些原因，有人认为社会性蜘蛛物种在进化时间上是不稳定的，因此社会性在蜘蛛中是一种罕见的现象。基于对Stegodyphus属的部分分子系统发育研究，我们探讨了该属中的社会性蜘蛛是进化上短暂存在的这一假说。我们估计了这三种社会性物种的出现时间，测试它们是代表祖先状态还是衍生状态，并评估相对于亚社会性同属物种的多样化情况。所有社会性物种的种内序列差异都很高，这并不支持它们是年轻的、短暂存在的物种这一观点。社会性谱系的出现时间、恒定的谱系分支以及社会性物种独立衍生的可能性表明，要么社会性物种“陷入了社会性状态”，要么它们已经进化为隐性物种。
