Background:Nest parasitism by cuckoos(Cuculus spp.)results in enormous reproductive failure and forces hosts to evolve antiparasitic strategies,i.e.,recognition of own eggs and rejection of cuckoo eggs.There are often...Background:Nest parasitism by cuckoos(Cuculus spp.)results in enormous reproductive failure and forces hosts to evolve antiparasitic strategies,i.e.,recognition of own eggs and rejection of cuckoo eggs.There are often sexual conflicts between male and female individuals in the expression of antiparasitic behavior due to the differences in reproductive inputs and division of labor.Methods:By adding a foreign egg made of blue soft clay to the host nest during early incubation period in the field,and by removing several host eggs and adding experimental eggs to control the proportion of two egg types in the nest,we examined egg rejection ability,egg recognition mechanism and sexual difference in egg rejection of the Oriental Reed Warbler(Acrocephalus orientalis),one of the major hosts of Common Cuckoos(Cuculus canorus).Results:Our results indicated that Oriental Reed Warblers can recognize and reject nearly 100%(73/75)of the nonmimetic eggs made of blue soft clay,and they could reject foreign eggs with 100%accuracy,regardless of the ratio of experimental eggs and its own eggs in the nest.Furthermore,all cases of egg rejections recorded by videos were only carried out by females.Conclusions:Oriental Reed Warblers have a high egg recognition ability and show a true recognition mechanism.Only female warblers perform egg rejection,suggesting that the sex for host egg incubation seems to play an important role in the evolution of egg recognition mechanisms.展开更多
基金supported by the National Natural Science Foundation of China(No.31970427 to WL and 32101242 to LM)by the Open Foundation of Hebei Key Laboratory of Wetland Ecology and Conservation(hklk201903 to LM)the Natural Science Foundation of Hebei Province of China(C2020101002 to LM)。
文摘Background:Nest parasitism by cuckoos(Cuculus spp.)results in enormous reproductive failure and forces hosts to evolve antiparasitic strategies,i.e.,recognition of own eggs and rejection of cuckoo eggs.There are often sexual conflicts between male and female individuals in the expression of antiparasitic behavior due to the differences in reproductive inputs and division of labor.Methods:By adding a foreign egg made of blue soft clay to the host nest during early incubation period in the field,and by removing several host eggs and adding experimental eggs to control the proportion of two egg types in the nest,we examined egg rejection ability,egg recognition mechanism and sexual difference in egg rejection of the Oriental Reed Warbler(Acrocephalus orientalis),one of the major hosts of Common Cuckoos(Cuculus canorus).Results:Our results indicated that Oriental Reed Warblers can recognize and reject nearly 100%(73/75)of the nonmimetic eggs made of blue soft clay,and they could reject foreign eggs with 100%accuracy,regardless of the ratio of experimental eggs and its own eggs in the nest.Furthermore,all cases of egg rejections recorded by videos were only carried out by females.Conclusions:Oriental Reed Warblers have a high egg recognition ability and show a true recognition mechanism.Only female warblers perform egg rejection,suggesting that the sex for host egg incubation seems to play an important role in the evolution of egg recognition mechanisms.
