Data from: Growth affects dispersal success in social mole-rats, but not the duration of philopatry

In naked mole-rats (Heterocephalus glaber), some non-breeding males show faster growth and are more likely to disperse than others. These differences have been suggested to be the result of a specialized developmental strategy leading to shorter philopatry and independent breeding, as opposed to extended philopatry as non-reproductive helpers. However, it is unclear whether fast-growing males disperse sooner than slow-growing males. An alternative explanation is that variation in quality between individuals causes high-quality individuals to grow quickly and maximize dispersal success without reducing philopatry. Here we show, that in Damaraland mole-rats (Fukomys damarensis), males that subsequently disperse successfully, grow faster than other non-reproductive males. This pattern is predicted by both hypotheses and does not discriminate between them. However, contrary to the suggestion that faster growth represents a developmental specialisation for early dispersal, fast-growing and slow-growing males remained equally long in their natal groups. Our study provides no evidence for adaptive divergence in male development leading either to early dispersal, or extended philopatry. Instead of representing specialized dispersers, fast-growing males of this species may be high-quality individuals.在裸鼹鼠（Heterocephalus glaber）种群中，部分非繁殖雄性个体相较于其他同类展现出更快的生长速率，且更倾向于扩散。此前有研究提出，此类差异源自一种特化的发育策略：相较于作为非繁殖帮手的长期恋巢行为（philopatry），该策略可缩短恋巢时长并实现独立繁殖；然而目前仍未明确，生长更快的雄性是否会比生长较慢的雄性更早扩散。另一种解释则认为，个体间的品质差异会促使优质个体更快生长，并在不缩短恋巢时长的前提下最大化扩散成功率。本研究以达马拉兰鼹鼠（Fukomys damarensis）为研究对象，结果显示，后续成功扩散的雄性个体，其生长速率快于其他非繁殖雄性，这一模式同时契合前述两种假说，无法对二者作出区分。但与“更快生长是为早期扩散形成的发育特化”这一观点相悖的是，生长较快与较慢的雄性个体在出生地种群中的停留时长并无显著差异。本研究未发现雄性发育存在适应性分化的证据——此类分化要么导向早期扩散，要么导向长期恋巢，该物种中生长较快的雄性并非特化的扩散者，反而可能属于优质个体。