Organisms allocate limited resources to competing activities such as reproduction, growth, and defense against parasites and predators. The introduction of a novel parasite may create new life history trade-offs. As hosts increase their investment in self-maintenance or defense, the cost of parasitism may carry over to other aspects of host biology. Here, in an experimental field study, we document delayed effects of an introduced nest parasite, Philornis downsi, on reproduction of Galápagos mockingbirds (Mimus parvulus). Parasitism of first nests reduced both the number and size of chicks that parents hatched when they re-nested several weeks later. The delayed effect of P. downsi on future reproduction may have been mediated by behavioral shifts by the parents to avoid or resist parasitism. Our results demonstrate that effects of parasitism can persist even after immediate exposure ends. We draw attention to the potential implications that introduced parasites have for host reproductive strategies.

中文翻译：

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侵入性巢蝇的寄生降低了加拉帕戈斯知更鸟的未来繁殖。

生物将有限的资源用于竞争活动，例如繁殖，生长以及对寄生虫和天敌的防御。新型寄生虫的引入可能会带来新的生活史权衡。随着宿主增加对自我维持或防御的投资，寄生虫的代价可能会转移到宿主生物学的其他方面。在这里，在一项实验性的现场研究中，我们记录了引入的巢寄生物Philornis downsi对加拉帕戈斯模仿鸟（Mimus parvulus）繁殖的延迟影响。第一窝的寄生减少了几周后重新筑巢时父母孵化的雏鸡的数量和大小。父母对避免或抵抗寄生虫的行为改变可能介导了P. downsi对未来生殖的延迟作用。我们的结果表明，即使在立即暴露结束后，寄生虫的影响仍会持续。我们提请注意引入的寄生虫对宿主繁殖策略的潜在影响。