Delehanty DJ, Fleischer RC, Colwell MA, Oring LW
Department of Biology, University of North Dakota at Grand Forks
Anim Behav. 1998 Apr;55(4):995-1002. doi: 10.1006/anbe.1997.0670.
Extra-pair fertilizations are common in birds, which has led to great interest in how this phenomenon is regulated at a proximate level and how extra-pair fertilizations, and extra-pair fertilization avoidance, shape avian social systems. In Wilson's phalaropes, Phalaropus tricolor, incubation and brood-rearing is performed exclusively by males. Males are able to rear only a single brood of four during a breeding season. This suggests that males have a high level of paternity in clutches and broods under their care and, thus, that extra-pair fertilizations are infrequent. In contrast, female social dominance, lack of territoriality and frequent interactions among breeding adults suggest that both males and females have the opportunity to engage in extra-pair copulations. Using DNA fingerprint band-sharing between putative parents and offspring, we found no evidence of extra-pair fertilizations among 51 offspring from 17 families of phalaropes. Copulation disruption by non-copulatory adults, ability of females to reject copulation attempts and potential fitness benefits to females by avoiding extra-pair fertilizations were sufficient to explain the absence of extra-pair fertilizations in Wilson's phalaropes. We propose that sex-role reversal affects the relative costs and benefits to females of seeking extra-pair fertilizations. At the time of clutch completion, females have invested particularly heavily in their clutches due to intense competition among females to gain and keep a mate during the pre-laying and laying periods. After clutch completion, nest success requires significant male parental care. Benefits to females in gaining extra-pair fertilizations may be offset by the risk of losing male parental care. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.
鸟类中配偶外受精现象很常见，这引发了人们对该现象在近因水平上如何受到调控，以及配偶外受精和避免配偶外受精如何塑造鸟类社会系统的浓厚兴趣。在威尔逊瓣蹼鹬（Phalaropus tricolor）中，孵化和育雏完全由雄性负责。雄性在一个繁殖季节只能养育一窝共四只雏鸟。这表明雄性对其照料下的窝卵数和雏鸟的父权比例很高，因此，配偶外受精情况并不常见。相比之下，雌性在社会中的主导地位、缺乏领地意识以及繁殖期成年个体之间频繁的互动表明，雄性和雌性都有机会进行配偶外交配。通过分析假定父母与后代之间的DNA指纹带共享情况，我们在来自17个瓣蹼鹬家族的51只后代中未发现配偶外受精的证据。非交配成年个体对交配的干扰、雌性拒绝交配尝试的能力以及避免配偶外受精给雌性带来的潜在适应性益处，足以解释威尔逊瓣蹼鹬中配偶外受精现象的缺失。我们认为，性别角色逆转会影响雌性寻求配偶外受精的相对成本和收益。在窝卵完成时，由于雌性在产卵前和产卵期间为获得并留住配偶而展开激烈竞争，它们在窝卵上投入了特别多的精力。窝卵完成后，巢穴的成功需要雄性大量的亲代抚育。雌性获得配偶外受精的益处可能会被失去雄性亲代抚育的风险所抵消。版权所有1998动物行为研究协会。版权所有1998动物行为研究协会。
