Data from: How cuckoos find and choose host nests for parasitism

How cuckoos find the nests of their hosts and choose nests with respect to egg phenotype for parasitism is a long-standing puzzle that has so far not been solved. We recently developed an experimental design to shed light on this mystery by studying the egg-laying behavior of common cuckoos (Cuculus canorus) in nests of its Oriental reed warbler (Acrocephalus orientalis) host. Our results showed that common cuckoos only parasitized host nests with host activities but ignored the egg phenotypes in the nests. Furthermore, cuckoos distinguished between nest types of black-browed reed warbler (Acrocephalus bistrigiceps) and Oriential reed warbler and chose to parasitize the latter. This study provides strong evidence for host activities being a prime factor affecting cuckoo parasitism. Cuckoos must first locate the general site of host nests from activities by the host and then target the nests for parasitism. These observations reject the optimal egg-laying hypothesis stating that cuckoos are capable of choosing to lay eggs in host nests with visually matching egg phenotypes. Therefore, our studies challenge the idea that cuckoos recognize eggs that match their own.

杜鹃如何找到宿主巢穴，并依据卵表型选择适宜寄生的巢穴，是一个长期以来悬而未决的经典谜题。本研究团队近期开发了一套实验方案，通过研究大杜鹃（Cuculus canorus）在其宿主东方大苇莺（Acrocephalus orientalis）巢穴中的产卵行为，以期揭开这一谜团。研究结果显示，大杜鹃仅会寄生存在宿主活动的巢穴，完全忽略巢穴内的卵表型特征。此外，杜鹃能够区分黑眉苇莺（Acrocephalus bistrigiceps）与东方大苇莺的巢穴类型，并优先选择寄生后者。本研究为"宿主活动是影响杜鹃寄生行为的核心调控因素"这一结论提供了坚实的实证支撑。杜鹃需首先通过宿主的活动定位宿主巢穴的大致区域，随后再锁定具体巢穴开展寄生行为。上述观测结果直接驳斥了"最优产卵假说"——该假说提出杜鹃能够选择与自身卵视觉特征匹配的宿主巢穴进行产卵。因此，本研究对"杜鹃能够识别与自身卵匹配的宿主卵"这一传统认知提出了挑战。