Institute of Cell and Systems Biology of Animals, Universität Hamburg, 20146, Hamburg, Germany.
Naturwissenschaften. 2022 Oct 29;109(6):51. doi: 10.1007/s00114-022-01826-5.
Extended phenotypes engineered by animals can potentially improve safety and/or foraging. Whether the well-known trade-off between safety and foraging applies for extended phenotypes, and if so, how it is resolved has not been determined. Spiders build elaborate silk structures that serve as traps for their insect prey and often attach silken retreats (nests) to their capture webs. These extended phenotypes of spiders are made of silk that is considered costly since it is made of protein. Using the Indian social spider, Stegodyphus sarasinorum, we examined how simple proximal factors, like colony hunger state and group size, shape trade-offs in collectively built extended phenotypes that offer shelter and food. We found that well-fed colonies showed greater investment in retreat silk than starved colonies. However, the two groups did not differ in their investment in capture webs. Hence, our findings validate the starvation-risk taking hypothesis in an extended phenotypic paradigm by showing that hungry colonies trade-off retreat size for capture web, irrespective of group size.
动物工程化的扩展表型可能会提高安全性和/或觅食能力。对于扩展表型，是否存在已知的安全性和觅食之间的权衡，以及如果存在，如何解决这个问题，目前还没有确定。蜘蛛会建造精心制作的丝绸结构作为它们昆虫猎物的陷阱，并且通常会将丝绸撤退（巢）附着在它们的捕获网上。蜘蛛的这些扩展表型是由被认为昂贵的丝绸制成的，因为它是由蛋白质组成的。使用印度社会性蜘蛛，Stegodyphus sarasinorum，我们研究了简单的近端因素，如殖民地饥饿状态和群体大小，如何影响提供庇护和食物的集体构建的扩展表型中的权衡。我们发现，饲养良好的殖民地比饥饿的殖民地在撤退丝绸上的投资更多。然而，这两个群体在捕获网上的投资没有差异。因此，我们的发现通过表明饥饿的殖民地为了捕获网而牺牲撤退的大小，验证了在扩展表型范式中的饥饿风险承担假说，而不管群体大小如何。
