The advance in breadth and depth of international arms control and disarma- ment has its great significance in eliminating the threat of a nuclear war and pro-pelling the world situation onward in the direction of rel...The advance in breadth and depth of international arms control and disarma- ment has its great significance in eliminating the threat of a nuclear war and pro-pelling the world situation onward in the direction of relaxation of tension. At thesame time, a negative trend also claims our attention. The strong military powerslike the United States are contending among themselves for retaining their militarysuperiority and seizing military sci-tech commanding heights while using展开更多
Nestling rejection is a rare type of host defense against brood parasitism compared with egg rejection.Theoretically,host defenses at both egg and nestling stages could be based on similar underlying discrimination me...Nestling rejection is a rare type of host defense against brood parasitism compared with egg rejection.Theoretically,host defenses at both egg and nestling stages could be based on similar underlying discrimination mechanisms but,due to the rarity of nestling rejector hosts,few studies have actually tested this hypothesis.We investigated egg and nestling discrimination by the fan-tailed gerygone Gerygone flavolateralis,a host that seemingly accepts nonmimetic eggs of its parasite,the shining bronze-cuckoo Chalcites lucidus,but ejects mimetic parasite nestlings.We introduced artificial eggs or nestlings and foreign gerygone nestlings in gerygone nests and compared begging calls of parasite and host nestlings.We found that the gerygone ejected artificial eggs only if their size was smaller than the parasite or host eggs.Ejection of artificial nestlings did not depend on whether their color matched that of the brood.The frequency of ejection increased during the course of the breeding season mirroring the increase in ejection frequency of parasite nestlings by the host.Cross-fostered gerygone nestlings were frequently ejected when lacking natal down and when introduced in the nest before hatching of the foster brood,but only occasionally when they did not match the color of the foster brood.Begging calls differed significantly between parasite and host nestlings throughout the nestling period.Our results suggest that the fan-tailed gerygone accepts eggs within the size range of gerygone and cuckoo eggs and that nestling discrimination is based on auditory and visual cues other than skin color.This highlights the importance of using a combined approach to study discrimination mechanisms of hosts.展开更多
文摘The advance in breadth and depth of international arms control and disarma- ment has its great significance in eliminating the threat of a nuclear war and pro-pelling the world situation onward in the direction of relaxation of tension. At thesame time, a negative trend also claims our attention. The strong military powerslike the United States are contending among themselves for retaining their militarysuperiority and seizing military sci-tech commanding heights while using
基金This study was funded by the National Science Centre,Poland:NCN 2012/05/E/NZ8/02694 and NCN 2016/23/B/NZ8/03082the Japan Society for Promotion of Science(JSPS):grant no.24-4578(to N.J.S.)+1 种基金24770028(to K.D.T.),23255004(to K.U.)by Rikkyo University:SFR 11-54(to N.J.S.).
文摘Nestling rejection is a rare type of host defense against brood parasitism compared with egg rejection.Theoretically,host defenses at both egg and nestling stages could be based on similar underlying discrimination mechanisms but,due to the rarity of nestling rejector hosts,few studies have actually tested this hypothesis.We investigated egg and nestling discrimination by the fan-tailed gerygone Gerygone flavolateralis,a host that seemingly accepts nonmimetic eggs of its parasite,the shining bronze-cuckoo Chalcites lucidus,but ejects mimetic parasite nestlings.We introduced artificial eggs or nestlings and foreign gerygone nestlings in gerygone nests and compared begging calls of parasite and host nestlings.We found that the gerygone ejected artificial eggs only if their size was smaller than the parasite or host eggs.Ejection of artificial nestlings did not depend on whether their color matched that of the brood.The frequency of ejection increased during the course of the breeding season mirroring the increase in ejection frequency of parasite nestlings by the host.Cross-fostered gerygone nestlings were frequently ejected when lacking natal down and when introduced in the nest before hatching of the foster brood,but only occasionally when they did not match the color of the foster brood.Begging calls differed significantly between parasite and host nestlings throughout the nestling period.Our results suggest that the fan-tailed gerygone accepts eggs within the size range of gerygone and cuckoo eggs and that nestling discrimination is based on auditory and visual cues other than skin color.This highlights the importance of using a combined approach to study discrimination mechanisms of hosts.
