Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the hos...Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the host. In this study, we investigated how egg-spot matching between the Common Cuckoo(Cuculus canorus) and its host, the Oriental Reed Warbler(Acrocephalus orientalis) is affected by the local parasitism rate, nest availability in breeding synchronization and egg rejection.Methods: We used the paired design of parasitized and their nearest non-parasitized nests where breeding occurred simultaneously to compare egg-spot matching. The image analysis was used to compare four eggshell pattern variables, namely spot size, density, coverage on the different areas of egg surface, and the distribution on the whole egg surface. Egg recognition experiments were conducted to test the effect of egg spots on egg rejection by the host.Results: Our results show that much better matching in almost all spot parameters tested on the side of the egg and the spot distribution on the whole egg occurred in parasitized nests than in non-parasitized nests. Matching of spot density between cuckoo and host eggs in parasitized nests increased with the synchronization between temporal availability of nests and the egg-laying period of female cuckoos. Egg recognition experiments in which the warbler eggs were deliberately painted with extra spots led to a significantly higher egg rejection rate(78.3%) than of unpainted eggs.Conclusion: Our data suggest that both the high temporal encounter rate between cuckoo and warbler nests as well as the high egg rejection ability of the host are important factors for egg-spot matching of the cuckoos.展开更多
Brood parasites,such as the Common Cuckoo(Cuculus canorus),rely on manipulating hosts from other species to raise their offspring.Selection should favor individuals that are able to identify and choose host nests that...Brood parasites,such as the Common Cuckoo(Cuculus canorus),rely on manipulating hosts from other species to raise their offspring.Selection should favor individuals that are able to identify and choose host nests that closely match the incubation stage of their own eggs.While intuitive,and supported by the findings of numerous longterm monitoring studies,experimental evidence of this remains sparse.By using video monitoring,we used three experimental groups to explore whether Common Cuckoos preferentially choose host Oriental Reed Warbler(Acrocephalus orientalis)nests that are early in their laying cycle.We found that Common Cuckoos preferentially parasitize nests of the host Oriental Reed Warbler that are earlier in their laying(less vs.more eggs)or nesting cycle(eggs vs.chicks),and videos of our experiments provide direct insights into their decision making process.Our results provide strong experimental evidence that Common Cuckoos are able to assess nesting stage and strategically choose nests that increase the likelihood of successful parasitism.展开更多
基金supported by the National Natural Science Foundation of China (Nos.31301888 and 31672316 to DL)the General Scientific Research Project of the Education Department of Liaoning Province (L2015196 to DL)the Open Fund of the Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, Beijing Normal University (K1401 to DL)
文摘Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the host. In this study, we investigated how egg-spot matching between the Common Cuckoo(Cuculus canorus) and its host, the Oriental Reed Warbler(Acrocephalus orientalis) is affected by the local parasitism rate, nest availability in breeding synchronization and egg rejection.Methods: We used the paired design of parasitized and their nearest non-parasitized nests where breeding occurred simultaneously to compare egg-spot matching. The image analysis was used to compare four eggshell pattern variables, namely spot size, density, coverage on the different areas of egg surface, and the distribution on the whole egg surface. Egg recognition experiments were conducted to test the effect of egg spots on egg rejection by the host.Results: Our results show that much better matching in almost all spot parameters tested on the side of the egg and the spot distribution on the whole egg occurred in parasitized nests than in non-parasitized nests. Matching of spot density between cuckoo and host eggs in parasitized nests increased with the synchronization between temporal availability of nests and the egg-laying period of female cuckoos. Egg recognition experiments in which the warbler eggs were deliberately painted with extra spots led to a significantly higher egg rejection rate(78.3%) than of unpainted eggs.Conclusion: Our data suggest that both the high temporal encounter rate between cuckoo and warbler nests as well as the high egg rejection ability of the host are important factors for egg-spot matching of the cuckoos.
基金supported by the National Natural Science Foundation of China(Nos.31960105 to LW,and 31970427 to WL)the specific research fund of the Innovation Platform for Academicians of Hainan Provincefunded by the Guizhou Natural Science Foundation(No.ZK[2022]-316)。
文摘Brood parasites,such as the Common Cuckoo(Cuculus canorus),rely on manipulating hosts from other species to raise their offspring.Selection should favor individuals that are able to identify and choose host nests that closely match the incubation stage of their own eggs.While intuitive,and supported by the findings of numerous longterm monitoring studies,experimental evidence of this remains sparse.By using video monitoring,we used three experimental groups to explore whether Common Cuckoos preferentially choose host Oriental Reed Warbler(Acrocephalus orientalis)nests that are early in their laying cycle.We found that Common Cuckoos preferentially parasitize nests of the host Oriental Reed Warbler that are earlier in their laying(less vs.more eggs)or nesting cycle(eggs vs.chicks),and videos of our experiments provide direct insights into their decision making process.Our results provide strong experimental evidence that Common Cuckoos are able to assess nesting stage and strategically choose nests that increase the likelihood of successful parasitism.