Data from: Phylogenetic tests reject Emery’s rule in the evolution of social parasitism in yellowjackets and hornets (Hymenoptera: Vespidae, Vespinae)

Social parasites exploit the brood-care behaviour and social structure of one or more host species. Within the social Hymenoptera, there are different types of social parasitism. In its extreme form, species of obligate social parasites, or inquilines, do not have the worker caste and depend entirely on the workers of a host species to raise their reproductive offspring. The strict form of Emery’s rule states that social parasites share immediate common ancestry with their hosts. Moreover, this rule has been linked with a sympatric origin of inquilines from their hosts. Here, we conduct phylogenetic analyses of yellowjackets and hornets based on 12 gene fragments and evaluate competing evolutionary scenarios to test Emery’s rule. We find that inquilines, as well as facultative social parasites, are not the closest relatives of their hosts. Therefore, Emery’s rule in its strict sense is rejected, suggesting that social parasites have not evolved sympatrically from their hosts in yellowjackets and hornets. However, the relaxed version of the rule is supported, since inquilines and their hosts belong to the same Dolichovespula clade. Furthermore, inquilinism has evolved only once in Dolichovespula.社会寄生生物（social parasites）会利用一种或多种寄主物种的育幼行为与社会结构。在社会性膜翅目（Hymenoptera）昆虫类群中，社会寄生现象存在多种类型。其中极端形式的专性社会寄生生物（obligate social parasites），又称寄食者（inquilines），不具备工蜂品级（worker caste），完全依赖寄主物种的工蜂来抚育其繁殖后代。埃默里法则（Emery’s rule）的严格版本指出，社会寄生生物与其寄主拥有最近的共同祖先。此外，该法则还与寄食者（inquilines）从寄主群体中同域起源（sympatric origin）的假说相关联。本研究基于12个基因片段（gene fragments）对黄胡蜂（yellowjackets）和胡蜂（hornets）开展系统发育分析（phylogenetic analyses），并评估多种竞争性进化情景（competing evolutionary scenarios）以检验埃默里法则。研究结果显示，寄食者（inquilines）以及兼性社会寄生生物（facultative social parasites）并非其寄主的最近缘类群。因此，严格版本的埃默里法则不成立，这表明在黄胡蜂与胡蜂类群中，社会寄生生物并非从寄主群体中同域演化而来。但该法则的宽松版本得到了支持，因为寄食者与其寄主同属于长黄胡蜂属（Dolichovespula）分支（clade）。此外，寄食型社会寄生（inquilinism）在长黄胡蜂属中仅演化出现过一次。