Ruch Jasmin, Riehl Torben, May-Collado Laura J, Agnarsson Ingi
Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia; Zoological Institute, Biocenter Grindel, University of Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
Center for Natural History, Zoological Museum Hamburg, University of Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
Mol Phylogenet Evol. 2015 Jan;82 Pt A:330-40. doi: 10.1016/j.ympev.2014.10.015. Epub 2014 Oct 28.
Determining factors that facilitate the transition from a solitary to a social lifestyle is a major challenge in evolutionary biology, especially in taxa that are usually aggressive towards conspecifics. Most spiders live solitarily and few species are known to be social. Nevertheless, sociality has evolved multiple times across several families and nearly all studied social lineages have originated from a periodically social (subsocial) ancestor. Group-living crab spiders (Thomisidae) are exclusively found in Australia and differ from most other social spiders because they lack a communal capture web. Three of the group-living species were placed in the genus Diaea and another in the genus Xysticus. Most Australian thomisids are, however, difficult to identify as most descriptions are old and of poor quality, and the genera Diaea and Xysticus may not correspond to monophyletic groups. Here, we clarify the phylogenetic relationships of the four group-living Australian thomisids and conclude that amongst these subsociality has evolved two to three times independently. The subsocial Xysticus bimaculatus is not closely related to any of the social Diaea and an independent origin of subsociality is likely in this case. The presented data indicates that within Diaea two origins of subsociality are possible. Our results help to understand the evolution of sociality in thomisids and support the hypothesis that permanent sociality in spiders has evolved multiple times relatively recently from subsocial ancestors.
确定促使从独居生活方式向群居生活方式转变的因素，是进化生物学中的一项重大挑战，尤其是在那些通常对同种个体具有攻击性的分类群中。大多数蜘蛛过着独居生活，已知只有少数物种是群居的。然而，群居习性在几个科中已经多次进化，几乎所有已研究的群居谱系都起源于周期性群居（亚社会性）的祖先。群居的蟹蛛（蟹蛛科）仅在澳大利亚被发现，并且与大多数其他群居蜘蛛不同，因为它们没有公共的捕猎网。其中三种群居物种被归入Diaea属，另一种被归入Xysticus属。然而，大多数澳大利亚蟹蛛很难鉴定，因为大多数描述都很陈旧且质量不佳，而且Diaea属和Xysticus属可能并不对应单系类群。在这里，我们阐明了四种群居的澳大利亚蟹蛛的系统发育关系，并得出结论，在这些物种中，亚社会性已经独立进化了两到三次。亚社会性的双斑Xysticus与任何群居的Diaea都没有密切关系，在这种情况下，亚社会性很可能有一个独立的起源。所呈现的数据表明，在Diaea属内，亚社会性有两种起源的可能性。我们的结果有助于理解蟹蛛科群居习性的进化，并支持这样一种假说，即蜘蛛的永久性群居习性是最近从亚社会性祖先多次进化而来的。
