Li Bin, Wang Longwu, Liu Jianping, Liang Wei
College of Biological Sciences and Engineering North Minzu University Yinchuan China.
Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences Hainan Normal University Haikou China.
Ecol Evol. 2025 Jan 7;15(1):e70825. doi: 10.1002/ece3.70825. eCollection 2025 Jan.
Recognising and rejecting parasitic eggs is one of the most common anti-parasitism strategies used by host birds. However, the egg rejection of some hosts exhibits behavioural plasticity. To investigate whether the egg rejection behaviour of host birds changes after encountering a parasitism event, we conducted egg rejection experiments on the locally most common host of the common cuckoo (), the grey bushchat () in Yunnan, China. When a single pure white egg of the white-rumped munia () or a blue model egg was individually added to the nest of the grey bushchat, the rejection rate for the white-rumped munia eggs was as high as 93.3%, whereas the rejection rate for the blue model egg was minimal (5.56%). However, when the grey bushchat rejected the munia egg and a blue model egg was subsequently added to its nest, the rejection rate for the blue model egg was significantly higher, reaching 54.5%. When recognised, the presence of a non-mimetic foreign egg in the nest may then act as a cue indicating high parasitism risk for the host. Consequently, the bird may intensify its inspection of nest eggs, leading to increased rejection of the previously accepted blue model eggs. Our results are consistent with the optimal acceptance threshold hypothesis, suggesting that as the parasitism risk increases, the grey bushchat adjusts its acceptance threshold for foreign eggs to become more stringent.
识别并拒绝寄生卵是宿主鸟类最常用的抗寄生策略之一。然而，一些宿主的卵拒绝行为表现出行为可塑性。为了研究宿主鸟类在遭遇寄生事件后其卵拒绝行为是否会发生变化，我们在中国云南对杜鹃（）当地最常见的宿主——灰林莺（）进行了卵拒绝实验。当将纯色的白腰文鸟（）白色卵或蓝色模型卵单独添加到灰林莺的巢中时，白腰文鸟卵的拒绝率高达93.3%，而蓝色模型卵的拒绝率极低（5.56%）。然而，当灰林莺拒绝了白腰文鸟卵并随后在其巢中添加一个蓝色模型卵时，蓝色模型卵的拒绝率显著更高，达到54.5%。当巢中出现一个非拟态的外来卵并被识别时，这可能会作为一种线索，向宿主表明寄生风险很高。因此，鸟类可能会加强对巢中卵的检查，导致对之前接受的蓝色模型卵的拒绝增加。我们的结果与最优接受阈值假说一致，表明随着寄生风险增加，灰林莺会调整其对外来卵的接受阈值，使其变得更加严格。
