Parejo Deseada, Avilés Jesús M
Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Aridas, C.S.I.C. C/General Segura 1, 04001, Almería, Spain.
Anim Cogn. 2007 Apr;10(2):81-8. doi: 10.1007/s10071-006-0055-2. Epub 2006 Dec 19.
Eavesdropping can be defined as the extraction of information from the interactions between other individuals. It provides a relatively cheap way of gathering relevant information for fitness enhancement. Here, we propose that obligate avian brood parasites, which always lay their eggs in foreign nests of individuals of other species, may eavesdrop on their host sexual signals to locate nests of high quality individuals in which to lay their parasitic eggs. Sexual signal variation can honestly signal parental quality. Thus, by eavesdropping on sexual signals, parasites may select high quality foster parents for their own offspring. Such a use of sexual signals within host populations by brood parasites differs from signal exploitation theory that proposes that parasite only use signals to locate potential host independently from signaller quality. Here, we review the avian literature concerning host choice within a host species by obligate avian brood parasites and find evidence for host selection within individuals of a host species on the basis of cues potentially functioning as sexually selected traits, or at least revealing parental abilities. We have also found support for the existence of benefits linked to host selection by avian brood parasites. Finally, one study reported on the attenuation of a sexual ornament in host populations under strong pressure by brood parasites. Most of these findings have been interpreted as evidence for host selection by avian brood parasites based on the conspicuousness of sexual signals. We suggest, however, that these findings may in fact reveal eavesdropping on host signalling performance by brood parasites which would use the information extracted to choose the better individuals among conspecifics of a given host. This provides a new perspective for the study of host selection in obligate brood parasites, and raises interesting questions for the study of animal cognition that would deserve experimental studies.
窃听可被定义为从其他个体之间的互动中提取信息。它为增强适应性收集相关信息提供了一种相对廉价的方式。在此，我们提出专性鸟类巢寄生者，即总是将卵产在其他物种个体的巢中的鸟类，可能会窃听其宿主的性信号，以找到高质量个体的巢来产下它们的寄生卵。性信号的变化能够诚实地反映亲代质量。因此，通过窃听性信号，寄生者可能会为自己的后代选择高质量的养父母。巢寄生者在宿主种群中对性信号的这种利用方式不同于信号利用理论，该理论认为寄生者仅利用信号来定位潜在宿主，而不考虑信号发出者的质量。在此，我们回顾了关于专性鸟类巢寄生者在宿主物种内选择宿主的鸟类文献，并找到了证据，表明在宿主物种的个体中，基于可能作为性选择特征发挥作用或至少能揭示亲代能力的线索进行宿主选择。我们还发现了支持鸟类巢寄生者进行宿主选择存在益处的证据。最后，一项研究报道了在巢寄生者的强大压力下，宿主种群中性装饰的衰减情况。这些发现大多被解释为鸟类巢寄生者基于性信号的显著性进行宿主选择的证据。然而，我们认为这些发现实际上可能揭示了巢寄生者对宿主信号表现的窃听行为，它们会利用提取到的信息在给定宿主的同种个体中选择更好的个体。这为专性巢寄生者的宿主选择研究提供了一个新视角，并为动物认知研究提出了有趣的问题，值得进行实验研究。
