Parenting strategies can be flexible within a species, and may have varying fitness effects. Understanding this flexibility and its fitness consequences is important for understanding why parenting strategies evolve. Here, we investigate the fitness consequences of flexible parenting in the burying beetle Nicrophorus orbicollis, a species known for its advanced provisioning behaviour of regurgitated vertebrate carrion to offspring by both sexes. We show that even when a parent is freely allowed to abandon the carcass at any point in time, biparental post-hatching care is the most common pattern of care adopted in N. orbicollis. Furthermore, two parents together raised more offspring than single parents of either sex, showing that the presence of the male can directly influences parental fitness even in the absence of competitors. This contrasts with studies in other species of burying beetle, where biparental families do not differ in offspring number. This may explain why biparental care is more common in N. orbicollis than in other burying beetles. We suggest how fitness benefits of two parents may play a role in the evolution and maintenance of flexible biparental care in N. orbicollis.

中文翻译：

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埋葬甲虫Nicrophorus orbicollis（鞘翅目：Silphidae）的双亲照顾是父母的主要和有益的。

育儿策略在一个物种内可能很灵活，并且可能具有不同的适应性效果。理解这种灵活性及其适应性后果对于理解为什么养育策略会变得很重要。在这里，我们研究了埋葬的甲虫Nicrophorus orbicollis中灵活育儿的适应性后果，该物种以其反刍脊椎动物腐肉对后代的先进供应行为而闻名。我们表明，即使在任何时间自由允许父母放弃屠体，双亲孵化后的照料也是N. orbicollis采用的最常见照料方式。此外，两个父母共同抚养的子女比任何性别的单亲父母都要多，这表明即使没有竞争者，男性的存在也​​可以直接影响父母的健康状况。这与其他埋藏甲虫物种的研究形成了鲜明对比，在其他物种中，双亲家庭的后代数量没有差异。这可能解释了为什么双亲保健在双唇猪笼草中比在其他埋藏的甲虫中更常见。我们建议两个父母的健身益处如何在双唇猪笼草的灵活双亲保健的发展和维持中发挥作用。