Parental care results in a greater mutation load, for which it is also a phenotypic antidote

Benevolent social behaviours, such as parental care, are predicted to relax selection against deleterious mutations, enabling them to persist. We tested this prediction experimentally using burying beetles, Nicrophorus vespilloides, which make an edible nest for their larvae, whom they nourish and defend. For 20 generations, we allowed replicate experimental burying beetle populations to evolve either with post-hatching care (‘Full Care’ populations) or without it (‘No Care’ populations). Lineages were seeded from these experimental populations and then inbred to expose differences in their mutation load. Outbred lineages served as controls. Half the lineages received post-hatching care, half did not. We found that inbred lineages derived from the Full Care populations had lower breeding success and went extinct more quickly than lineages derived from the No Care populations – but only when offspring received no post-hatching care. We infer that Full Care lineages carried more recessive..., ,

诸如育幼行为在内的善意社会行为，据预测可缓解针对有害突变的选择压，从而使有害突变得以保留存续。我们以斑埋葬甲（Nicrophorus vespilloides）为实验对象验证了这一预测：该物种会为幼虫构筑可食用的巢穴，并对幼虫进行抚育与防御。我们让多组重复实验的埋葬甲种群历经20代演化，其中一组为孵化后育幼组（以下简称‘全育组’种群），另一组则无孵化后育幼行为（以下简称‘无育组’种群）。从上述实验种群中分离出各世系，随后通过近交使其突变负荷的差异得以显现；以远交世系作为对照。其中半数世系接受孵化后育幼处理，另一半则不接受。我们发现，仅当后代未获得孵化后育幼时，源自全育组种群的近交世系，其繁殖成功率低于源自无育组种群的世系，且灭绝速度更快。我们据此推断，全育组世系携带更多隐性……