Why cuckoos should parasitize parrotbills by laying eggs randomly rather than laying eggs matching the egg appearance of parrotbill hosts?

作     者：Canchao Yang Fugo Takasu Wei Liang Anders P Moller 

作者机构：Ministry of Education Key Laboratory for Tropical Plant and Animal EcologyCollege of Life SciencesHainan Normal University Department of Information and Computer SciencesNara Women’s University Laboratoired’EcologieSystématique et EvolutionCNRS UMR 8079Universite Paris-Sud 

出 版 物：《Chinese Birds》 (中国鸟类（英文版）)

年 卷 期：2015年第6卷第2期

页      面：53-59页

核心收录：

学科分类：07[理学] 0713[理学-生态学] 

基　　金：funded by the National Natural Science Foundation of China(nos.31071938,31272328 and 31472013 to WL,and 31260514 to CY) the Program for New Century Excellent Talents in University(NCET-13-0761) the Key Project of the Chinese Ministry of Education(no.212136) the Program of International S&T Cooperation(KJHZ2013-12)to CY 

主　　题：Host imprint Egg laying behavior Egg color Host selection Common cuckoo Egg polymorphy 

摘      要：The coevolutionary interaction between cuckoos and their hosts has been studied for a long time, but to date some puzzles still remain unsolved. Whether cuckoos parasitize their hosts by laying eggs randomly or matching the egg morphs of their hosts is one of the mysteries of the cuckoo problem. Scientists tend to believe that cuckoos lay eggs matching the appearance of host eggs due to selection caused by the ability of the hosts to recognize their own *** this paper, we first review previous empirical studies to test this mystery and found no studies have provided direct evidence of cuckoos choosing to parasitize host nests where egg color and pattern match. We then present examples of unmatched cuckoo eggs in host nests and key life history traits of cuckoos, e.g. secretive behavior and rapid egg-laying and link them to cuckoo egg laying behavior. Finally we develop a conceptual model to demonstrate the egg laying behaviour of cuckoos and propose an empirical test that can provide direct evidence of the egg-laying properties of female cuckoos. We speculate that the degree of egg matching between cuckoo eggs and those of the host as detected by humans is caused by the ability of the hosts to recognize their own eggs, rather than the selection of matching host eggs by cuckoos. The case of Common Cuckoos(Cuculus canorus) and their parrotbill hosts(Paradoxornis alphonsianus), where it has been shown that both have evolved polymorphic eggs(mainly blue and white), was used to develop a conceptual model to demonstrate why cuckoos should utilize parrotbill hosts by laying eggs randomly rather than laying eggs matching the appearance of host *** conclusion, we found no evidence for the hypothesis that cuckoos lay eggs based on own egg color matching that of the parrotbill-cuckoo system. We argue theoretically that laying eggs matching those of the hosts in this system violates a key trait of the life history of cuckoos and therefore should be maladaptive.