Grinsted Lena, Agnarsson Ingi, Bilde Trine
Department of Bioscience, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark.
Naturwissenschaften. 2012 Dec;99(12):1021-30. doi: 10.1007/s00114-012-0983-4. Epub 2012 Oct 24.
Cooperation and group living often evolves through kin selection. However, associations between unrelated organisms, such as different species, can evolve if both parties benefit from the interaction. Group living is rare in spiders, but occurs in cooperative, permanently social spiders, as well as in territorial, colonial spiders. Mixed species spider colonies, involving closely related species, have rarely been documented. We examined social interactions in newly discovered mixed-species colonies of theridiid spiders on Bali, Indonesia. Our aim was to test the degree of intra- and interspecific tolerance, aggression and cooperation through behavioural experiments and examine the potential for adoption of foreign brood. Morphological and genetic analyses confirmed that colonies consisted of two related species Chikunia nigra (O.P. Cambridge, 1880) new combination (previously Chrysso nigra) and a yet undescribed Chikunia sp. Females defended territories and did not engage in cooperative prey capture, but interestingly, both species seemed to provide extended maternal care of young and indiscriminate care for foreign brood. Future studies may reveal whether these species adopt only intra-specific young, or also inter-specifically. We classify both Chikunia species subsocial and intra- and interspecifically colonial, and discuss the evolutionary significance of a system where one or both species may potentially benefit from mutual tolerance and brood adoption.
合作与群居行为通常通过亲缘选择而进化。然而，如果双方都能从互动中受益，那么不相关的生物体之间的关联，比如不同物种之间的关联，也能够进化。群居行为在蜘蛛中较为罕见，但在具有合作性的永久性社会性蜘蛛以及领地性、集群性蜘蛛中会出现。涉及亲缘关系较近物种的混合物种蜘蛛群落很少有记录。我们研究了在印度尼西亚巴厘岛新发现的球蛛科蜘蛛混合物种群落中的社会互动。我们的目的是通过行为实验来测试种内和种间的容忍度、攻击性与合作程度，并研究收养外来幼蛛的可能性。形态学和遗传学分析证实，这些群落由两个亲缘关系较近的物种组成，即黑点奇蛛（Chikunia nigra，新组合，原名为Chrysso nigra，由O.P. 剑桥于1880年命名）和一个尚未描述的奇蛛属物种。雌性蜘蛛会保卫领地，并不参与合作捕食，但有趣的是，这两个物种似乎都会为幼蛛提供长期的母性照料，并且对外来幼蛛一视同仁。未来的研究可能会揭示这些物种是只收养同种幼蛛，还是也会收养不同种幼蛛。我们将这两个奇蛛属物种归类为亚社会性物种，并且具有种内和种间集群性，同时还讨论了这样一种系统的进化意义，即其中一个或两个物种可能会从相互容忍和收养幼蛛中潜在受益。
