Data from: Difference in parenting in two species of burying beetle, Nicrophorus orbicollis and Nicrophorus vespilloides

Burying beetles (Nicrophorus) are model parents among insects, with all studied species known to regurgitate flesh from vertebrate carcasses to their offspring. However, most studies focus on a very few species, yet the interpretation of the function and importance of care is typically generalized to all burying beetles. Here we characterize subtle variation within and between individuals and sexes, and how this variation differs between two species of burying beetle. We find that Nicrophorus orbicollis exhibits low variance, with a normal distribution of parental care provided during peak care periods. In N. vespilloides, however, the distribution is more uniform as values of care are spread across the possible phenotypic spectrum. This suggests that there is stabilizing selection on care in N. orbicollis, but relaxed or disruptive selection in N. vespilloides. Although repeatability was similar between both species, transitions from other care behaviors into feeding were more common in N. orbicollis than N. vespilloides. Thus, while parenting is coarsely similar across the genus, variation in its expression should not be extrapolated to all Nicrophorus. We suggest that subtle variation both within and among species merits greater attention, and could inform us about the factors that lead to different distributions of care.埋葬甲属（Nicrophorus）昆虫堪称昆虫界的模范双亲，所有已被研究的物种均会通过反刍脊椎动物腐肉的方式为后代提供食物。然而，当前绝大多数研究仅聚焦于极少数物种，且通常将针对这些少数物种的亲代抚育功能与重要性的解读，泛化至所有埋葬甲属昆虫。本研究系统表征了两种葬甲属昆虫个体间、雌雄间的细微差异，以及该类差异在两物种间的分化特征。研究发现，圆胸葬甲（Nicrophorus orbicollis）的亲代抚育行为方差较低，在抚育高峰期的抚育行为呈现正态分布；而黑埋葬甲（Nicrophorus vespilloides）的抚育行为分布则更为均匀，抚育值覆盖了全部可能的表型谱。这提示，圆胸葬甲的亲代抚育行为受到稳定选择作用，而黑埋葬甲的亲代抚育则处于放松选择或歧化选择之下。尽管两物种的亲代抚育行为重复性相近，但从其他抚育行为转向喂食行为的频次，圆胸葬甲显著高于黑埋葬甲。综上，尽管葬甲属内的双亲抚育行为大致相似，但我们不应将单一物种的抚育行为差异外推至整个葬甲属。我们认为，物种内部以及物种间的细微差异值得更多关注，这类差异或可帮助我们解析驱动不同抚育行为分布格局的核心因素。