大杜鹃对北红尾鸲的放牧行为

Farming Behavior by the Common Cuckoos in Its Daurian Redstart Hosts

在宿主的寄生防御压力下,鸟类巢寄生者通常会进化出一系列有效的寄生行为以提高其自身的繁殖适合度。以往研究发现,部分巢寄生者可能具有类似人类的“放牧”行为,即通过破坏或捕食不适合寄生的宿主巢,促使其重新筑巢以获取新的寄生机会。然而,对于其野外行为事件的报道并不多见。2018年5至8月,在贵州六枝地区,通过对宿主北红尾鸲(Phoenicurus auroreus)的巢进行录像监控,首次记录到大杜鹃(Cuculus canorus)对正在孵卵的北红尾鸲的放牧行为。进一步查阅了大杜鹃寄生系统中已有的放牧案例,说明放牧行为很可能是大杜鹃普遍采用的一种寄生策略。

Obligate avian brood parasites lay their eggs in nests belonging to other host species,accordingly,they imposed the costs of parental care to their victims.Hosts evolve defenses to counter brood parasitism such as egg recognition and egg rejection,also nest defense,these host-parasites system well-known arms race are regarded as a textbook example of co-evolutionary Interactions.Natural selection favors the brood parasites such as parasitic cuckoos to evolve effective parasitic strategies under the pressure of anti-parasitism to improve their reproductive fitness.Previous studies revealed that some brood parasites might take the“farming”strategy,which means that they would destroy the content(eggs/nestlings)of host nests,forcing the hosts to re-nest,so they could gain new parasitic opportunities.However,reports on such events in the field are extremely rare in all avian parasitism systems.In May 2018,one case of such farming behavior by the Common Cuckoo(Cuculus canorus)in its Daurian Redstart(Phoenicurus auroreus)host was confirmed by the video recording in Liuzhi area of Guizhou Province,China.By reviewing literatures about farming behaviors in the Common Cuckoo(Table 1),we found that the farming behavior of the Common Cuckoo being more common than previously thought,and the strategy could increase its breeding success.