Parental care is a costly behaviour that raises the prospects of offspring survival. In species with biparental care these costs are shared by both parents, although there may be a conflict regarding the relative investment of each sex. Avian brood parasites leave all the costs of rearing offspring to their hosts. The magnitude of these costs and their consequences on the relative role of both sexes in parental care and future reproduction remain mostly unknown. Here, we investigate whether provisioning rate of nestlings by magpie hosts Pica pica differs between broods parasitized by the great spotted cuckoo Clamator glandarius and non‐parasitized broods, and whether the relative contribution of each sex to provisioning is affected by parasitism. Furthermore, we explore the effect of parasitism on magpie's future reproduction. We found that provisioning rate was similar in parasitized and non‐parasitized broods, and that the relative contribution of males and females was also similar, irrespectively of the parasitism status. However, rearing parasitic offspring seems to have a negative long‐term effect on magpie's breeding phenology in the following breeding season. Our results suggest that, although brood parasitism by great spotted cuckoos does not seem to influence the relative contribution of both sexes to parental care, it may entail long‐term extra costs in terms of breeding delay for magpies.

中文翻译：

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雄性和雌性喜hosts寄主的巢寄生，供应率和繁殖物候

父母照料是一种代价高昂的行为，增加了后代的生存前景。在具有双亲照顾的物种中，这些成本由父母双方共同承担，尽管在每种性别的相对投资方面可能存在冲突。禽类寄生虫将抚养后代的所有费用留给了寄主。这些费用的数额及其对两性在父母照料和未来生育中的相对作用的影响仍然未知。在这里，我们调查了喜hosts寄主皮卡·皮卡（Pica pica）的雏鸟提供率是否在大斑杜鹃Clamator glandarius寄生的雏鸟之间有所不同和未寄生的亲戚，以及每种性别对供应的相对贡献是否受寄生虫影响。此外，我们探讨了寄生对喜s未来繁殖的影响。我们发现，在寄生和未寄生的群体中，配给率相似，并且不论寄生状态如何，雄性和雌性的相对贡献也相似。然而，在接下来的繁殖季节中，寄生后代的饲养似乎会对喜p的繁殖物候产生长期的负面影响。我们的研究结果表明，尽管斑点杜鹃的育雏寄生似乎并不影响两性在父母照料中的相对贡献，但就喜delay的繁殖延迟而言，这可能需要长期的额外费用。