Data from: Intergenerational effects of inbreeding in Nicrophorus vespilloides: offspring suffer fitness costs when either they or their parents are inbred

Inbreeding depression is the reduction in fitness caused by mating between related individuals. Inbreeding is expected to cause a reduction in offspring fitness when the offspring themselves are inbred, but outbred individuals may also suffer a reduction in fitness when they depend on care from inbred parents. At present, little is known about the significance of such intergenerational effects of inbreeding. Here, we report two experiments on the burying beetle Nicrophorus vespilloides, an insect with elaborate parental care, in which we investigated inbreeding depression in offspring when either the offspring themselves or their parents were inbred. We found substantial inbreeding depression when offspring were inbred, including reductions in hatching success of inbred eggs and survival of inbred offspring. We also found substantial inbreeding depression when parents were inbred, including reductions in hatching success of eggs produced by inbred parents and survival of outbred offspring that received care from inbred parents. Our results suggest that intergenerational effects of inbreeding can have substantial fitness costs to offspring, and that future studies need to incorporate such costs to obtain accurate estimates of inbreeding depression.

近交衰退（inbreeding depression）指亲缘个体间交配所引发的适合度（fitness）下降。当子代自身发生近交（inbred）时，近交通常会导致子代适合度降低；但当远交（outbred）个体依赖近交亲本的抚育时，其自身适合度也可能出现下降。目前学界对这类近交的代际效应（intergenerational effects）的重要性仍知之甚少。本研究针对具有复杂双亲抚育行为的埋葬甲（Nicrophorus vespilloides）开展两项实验，探究了当子代自身发生近交，或是其亲本发生近交时，子代所面临的近交衰退情况。我们发现，子代发生近交时会出现显著的近交衰退，具体表现为近交卵的孵化成功率下降，以及近交子代的存活率降低。同时我们还发现，亲本发生近交时同样会出现显著的近交衰退，具体表现为近交亲本所产卵的孵化成功率下降，以及接受近交亲本抚育的远交子代的存活率降低。本研究结果表明，近交的代际效应会对子代造成显著的适合度代价，未来相关研究需纳入此类代价，才能对近交衰退做出准确评估。