Giroux Marie-Andrée, Ditlecadet Delphine, Martin Luc J, Lanctot Richard B, Lecomte Nicolas
Canada Research Chair in Polar and Boreal Ecology, Université de Moncton, Moncton, Canada; Centre d'Études Nordiques, Université du Québec à Rimouski, Rimouski, Canada; Canada Research Chair on Northern Biodiversity, Université du Québec à Rimouski, Rimouski, Canada.
Molecular Biology Unit, Fisheries and Oceans Canada , Moncton , Canada.
PeerJ. 2016 May 2;4:e1989. doi: 10.7717/peerj.1989. eCollection 2016.
Sex-role reversal, in which males care for offspring, can occur when mate competition is stronger between females than males. Secondary sex traits and mate attracting displays in sex-role-reversed species are usually more pronounced in females than in males. The red phalarope (Phalaropus fulicarius) is a textbook example of a sex-role-reversed species. It is generally agreed that males are responsible for all incubation and parental care duties, whereas females typically desert males after having completed a clutch and may pair with new males to lay additional clutches. The breeding plumage of female red phalaropes is usually more brightly colored than male plumage, a reversed sexual dichromatism usually associated with sex-role reversal. Here, we confirm with PCR-based sexing that male red phalaropes can exhibit both the red body plumage typical of a female and the incubation behavior typical of a male. Our result, combined with previous observations of brightly colored red phalaropes incubating nests at the same arctic location (Igloolik Island, Nunavut, Canada), suggests that plumage dichromatism alone may not be sufficient to distinguish males from females in this breeding population of red phalaropes. This stresses the need for more systematic genetic sexing combined with standardized description of intersexual differences in red phalarope plumages. Determining whether such female-like plumage on males is a result of phenotypic plasticity or genetic variation could contribute to further understanding sex-role reversal strategies in the short Arctic summer.
当雌性之间的配偶竞争比雄性更强时，就会出现雄性照顾后代的性别角色逆转现象。在性别角色逆转的物种中，第二性征和吸引配偶的展示通常在雌性中比在雄性中更明显。红颈瓣蹼鹬（Phalaropus fulicarius）是性别角色逆转物种的典型例子。人们普遍认为，雄性负责所有的孵化和育雏工作，而雌性通常在产完一窝卵后就离开雄性，可能会与新的雄性配对产下更多窝卵。雌性红颈瓣蹼鹬的繁殖羽通常比雄性羽颜色更鲜艳，这种性二态性的逆转通常与性别角色逆转有关。在这里，我们通过基于聚合酶链反应（PCR）的性别鉴定证实，雄性红颈瓣蹼鹬既可以表现出雌性典型的红色体羽颜色，也可以表现出雄性典型的孵化行为。我们的结果，结合之前在同一北极地点（加拿大努纳武特地区伊格卢利克岛）观察到的颜色鲜艳的红颈瓣蹼鹬孵巢现象，表明仅靠羽色二态性可能不足以在这个红颈瓣蹼鹬繁殖种群中区分雄性和雌性。这强调了需要更系统的遗传性别鉴定，并结合对红颈瓣蹼鹬羽色两性差异的标准化描述。确定雄性身上这种类似雌性的羽色是表型可塑性还是遗传变异的结果，可能有助于进一步理解北极短暂夏季中的性别角色逆转策略。
