social_codings_pruned.csv from Phylogeny of the carpenter bees (Apidae: Xylocopinae) highlights repeated evolution of sociality

Many groups of animals have evolved social behaviours in different forms, from intimate familial associations to the complex eusocial colonies of some insects. The subfamily Xylocopinae, including carpenter bees and their relatives, is a diverse clade exhibiting a wide range of social behaviours, from solitary to obligate eusociality with distinct morphological castes, making them ideal focal taxa in studying the evolution of sociality. We used ultraconserved element data to generate a broadly sampled phylogeny of the Xylocopinae, including several newly sequenced species. We then conducted ancestral state reconstructions on the evolutionary history of sociality in this group under multiple coding models. Our results indicate solitary origins for the Xylocopinae with multiple transitions to sociality across the tree and subsequent reversals to solitary life, demonstrating the lability and dynamic nature of social evolution in carpenter bees. Ultimately, this work clarifies the evolutionary history of the Xylocopinae, and expands our understanding of independent origins and gains and losses of social complexity.

诸多动物类群均演化出形式各异的社会行为，从亲密的家族社群到部分昆虫所形成的复杂真社会性（eusociality）集群。木蜂亚科 (Xylocopinae) 包含木蜂及其近缘类群，是一个物种丰富的演化支系，其社会行为跨度极大，从独居生活到具有明确形态品级的专性真社会性均有分布，因此成为研究社会行为演化的理想模式类群。本研究利用超保守元件 (ultraconserved element, UCE) 数据，对木蜂亚科开展了广取样的系统发育分析，涵盖多个新测序的物种。随后，我们基于多种编码模型，对该类群社会行为的演化历史开展了祖先状态重构。研究结果表明，木蜂亚科的祖先社会状态为独居，其后在演化树上多次出现向社会性生活的过渡，且存在数次重回独居状态的演化反转，这证实了木蜂类群社会演化的可塑性与动态特征。本研究厘清了木蜂亚科的演化历史，拓展了学界对社会复杂性独立起源、获得与丢失的认知。