Ashworth Laboratories, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.
J Evol Biol. 2020 Nov;33(11):1567-1578. doi: 10.1111/jeb.13692. Epub 2020 Sep 14.
Parents and offspring have different optima for the level of parental resource allocation and the timing of nutritional independence. Theoretical models assume that either parents or offspring control the allocation of resources within a brood; however, control may also be mutual. Here, we investigate whether the resolution of parent-offspring conflict is biased towards cues from either the parents' or the offspring's behaviour, or whether the conflict is under mutual control. Importantly, we considered potential shifts in the power continuum over the entire period of juvenile dependency. The burying beetle Nicrophorus vespilloides parents provision food for the larvae, and the larvae solicit food from their parents with conspicuous begging displays. Both parental and larval behaviours change as larvae age. We repeatedly manipulated the age of the brood females care for, thereby creating mismatch between the age of the foster brood and expected age of the brood from the female parent's perspective, over the period of dependency in juvenile development. We found that females adjusted the total amount of provisioning based on the actual age of the brood. However, both the parent and the offspring influenced the levels of food provisioning, which followed neither the expected age of the brood from the parent's perspective nor offspring age. Our results suggest that there is mutual control over parental care, thus contradicting the dichotomous view of control over parental care. We suggest that the mutual influence of both parents and the offspring should be taken into account in development of future theory, as well as empirical studies.
父母和后代在父母资源分配水平和营养独立时间上有不同的最优选择。理论模型假设父母或后代中的一方控制亲代资源的分配;然而,控制也可能是相互的。在这里,我们调查父母和后代的行为线索是否会影响亲代-后代冲突的解决,还是冲突受到双方的共同控制。重要的是,我们考虑了在整个幼体依赖期权力动态的潜在变化。埋葬虫 Nicrophorus vespilloides 的亲代会为幼虫提供食物,而幼虫则会通过显眼的乞讨行为向亲代索要食物。父母和幼虫的行为都会随着幼虫的年龄而变化。我们反复操纵亲代照顾的幼虫的年龄,从而在幼体发育的依赖期内,人为地制造了育雏年龄与亲代预期育雏年龄之间的不匹配。我们发现,雌性会根据育雏的实际年龄来调整总的喂食量。然而,亲代和后代都影响着食物的供给水平,既不符合亲代从自身角度对育雏的预期年龄,也不符合后代的年龄。我们的研究结果表明,亲代照顾存在双方的共同控制,这与亲代照顾控制的二分法观点相矛盾。我们建议,未来的理论发展以及实证研究都应该考虑到父母和后代的相互影响。