Parental effects on inbreeding depression in a beetle with obligate parental care

Inbreeding depression occurs when individuals who are closely related mate and produce offspring with reduced fitness. Although inbreeding depression is a genetic phenomenon, the magnitude of inbreeding depression can be influenced by environmental conditions and parental effects. In this study, we tested whether size-based parental effects influence the magnitude of inbreeding depression in an insect with elaborate and obligate parental care (the burying beetle, Nicrophorus orbicollis). We first tested for size-dependent maternal effects on offspring size using a phenotypic manipulation experiment where we created large and small adults by manipulating the amount of time they fed as larvae. Consistent with studies of other Nicrophorus species, we found that larger mothers produced larger offspring. We next tested for size-dependent parental effects on the magnitude of inbreeding depression in two traits: mean larval mass and survival from larval dispersal to eclosion. As in our first e..., ,近交衰退（inbreeding depression）指亲缘关系较近的个体交配后，所产后代适合度（fitness）降低的生物学现象。尽管近交衰退属于遗传范畴，但其强度可受环境条件与亲本效应（parental effects）的调控。本研究以一种具有复杂专性亲代抚育行为的昆虫——圆胸埋葬甲（Nicrophorus orbicollis）为研究对象，探究基于体型的亲本效应是否会影响其近交衰退的强度。我们首先通过表型操控实验（phenotypic manipulation experiment）检验母本体型对后代体型的依赖效应：通过调控幼虫阶段的取食时长，将成虫划分为大型与小型两组。与其他埋葬甲属（Nicrophorus）物种的已有研究结果一致，我们发现体型更大的母本所产后代体型也更大。随后，我们针对两个性状——平均幼虫体重以及幼虫扩散至羽化的存活率，检验了亲本体型对近交衰退强度的影响效应。正如我们首项实验的……