Several previous studies have indicated that nest sanitation behavior is a general adaptation in altricial birds,with egg recog nition capacity evolvi ng as a specific response to in terspecific brood parasitism(IBP)....Several previous studies have indicated that nest sanitation behavior is a general adaptation in altricial birds,with egg recog nition capacity evolvi ng as a specific response to in terspecific brood parasitism(IBP).However,a rece nt study suggested an alternative hypothesis,con cludi ng that con specific brood parasitism(CBP)selects for egg rejection in thrushes,with IBP as a by-product.In the present study,we used a spectrophotometer to quantify egg coloration and egg mimicry and performed artificial parasitism experiments in the grey?backed thrush(Turdus hortulorum).We showed that individuals of this species rejected 100%of 12 foreign eggs,without IBP or CBP detected.In a review of previous studies,we also discuss possible explanations for the high egg rejection rate in the grey-backed thrush and suggest areas for future study.Altricial birds have evolved advaneed reproductive behavior to in crease the fitn ess of their offspring by buildi ng elaborate structures(i.e.,nests),in which they lay eggs and rear their nestlings(Hansell,2000).Bird nests not only provide a suitable place for nestling development,but also act as a concealed location for safety from predators.Furthermore,bird parents have evolved nest sanitation behavior to clean foreig n objects from their n ests,in eluding feces,eggshells,branches,and leaves,because they induce predation,facilitate microorganism growth,damage eggs,or hurt nestlings during brooding(Guigueno&Sealy,2012).Therefore,nest sanitation has evolved as a general behavior in altricial birds for distinguishing between egg-shaped and non-egg-shaped objects.展开更多
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
基金supported by the National Natural Science Foundation of China(31672303 to C.Y.,31660617 to L.W.and 31472013 and 31772453 to W.L.)
文摘Several previous studies have indicated that nest sanitation behavior is a general adaptation in altricial birds,with egg recog nition capacity evolvi ng as a specific response to in terspecific brood parasitism(IBP).However,a rece nt study suggested an alternative hypothesis,con cludi ng that con specific brood parasitism(CBP)selects for egg rejection in thrushes,with IBP as a by-product.In the present study,we used a spectrophotometer to quantify egg coloration and egg mimicry and performed artificial parasitism experiments in the grey?backed thrush(Turdus hortulorum).We showed that individuals of this species rejected 100%of 12 foreign eggs,without IBP or CBP detected.In a review of previous studies,we also discuss possible explanations for the high egg rejection rate in the grey-backed thrush and suggest areas for future study.Altricial birds have evolved advaneed reproductive behavior to in crease the fitn ess of their offspring by buildi ng elaborate structures(i.e.,nests),in which they lay eggs and rear their nestlings(Hansell,2000).Bird nests not only provide a suitable place for nestling development,but also act as a concealed location for safety from predators.Furthermore,bird parents have evolved nest sanitation behavior to clean foreig n objects from their n ests,in eluding feces,eggshells,branches,and leaves,because they induce predation,facilitate microorganism growth,damage eggs,or hurt nestlings during brooding(Guigueno&Sealy,2012).Therefore,nest sanitation has evolved as a general behavior in altricial birds for distinguishing between egg-shaped and non-egg-shaped objects.
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.
