Benefit And Cost For Extra-pair Copulations In Male Yellow-rumped Flycatcher (Ficedula Zanthopygia)

Extra-Pair Copulation(EPC)is widespread among avian species,and more than 70% of the Passeriformes birds have extra-pair mating behavior,and strict genetic monogamy is less than 25%.In the early study,it was found that the proportion of the extra-pair about Yellow-rumped Flycatcher(Ficedula zanthopygia)was higher in the Zuo jia Nature Reserve.We carried out a research during breeding seasons of 2015-2016(April-July).The study include 3 parts: a half-day observation of mate guarding during the egg laying period;the nest defensive experiment by the parent birds during the incubation period;provisioning rate of parent during the breeding period.In the present study,we aimed to check the relatedness between benefit and cost of male Yellow-rumped Flycatcher in extra-pair copulation.During the study period,a total of 48 nests were found,25 of which were extra-pair nests;In 245 nestlings,there are 65 extra-pair offspring,EPC occurrence rate is 52.1%.We found the total numbers of genetic offspring of the males make others cuckold have significant more than the males who were cuckolds.There was no significant correlation between mate guarding intensity and proportion of extra-pair paternity,and positive correlation between male composite body size indicators with male mate guarding intensity.For the nest defensive experiments of parent birds show: the defensive intensity was no significant difference between males and females;it was no correlation between the defensive intensity of males and proportion of extra-pair paternity,between the defensive intensity of males and the numbers of extra-pair offspring in other nests,and between the defensive intensity of male and the clutch sizes.For the provisioning experiments of parent bird show: the provisioning rate of females was more than males';there was no significant correlation between the provisioning rate of males and of extra-pair paternity.The provisioning rates of males and females were no significant difference between extra-pair paternity and no extra-pair paternity.We found there existed significant positive correlation between provisioning rates and composite body size indicators of males.The results suggested that the male may get more the numbers of offspring through extra-pair copulation,increase the breeding fitness;the behavior of the mate guard by males couldn't prevent its loss paternity,and the numbers of extra-pair offspring was no affection on the defensive intensity and provisioning rates of males.