Barve Sahas, Riehl Christina, Walters Eric L, Haydock Joseph, Dugdale Hannah L, Koenig Walter D
Division of Birds, Smithsonian National Museum of Natural History, 10th Street and Constitution Avenue NW, Washington, DC 20560, USA.
Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ 08544, USA.
Proc Biol Sci. 2021 Aug 25;288(1957):20210579. doi: 10.1098/rspb.2021.0579. Epub 2021 Aug 18.
Cooperative breeding strategies lead to short-term direct fitness losses when individuals forfeit or share reproduction. The direct fitness benefits of cooperative strategies are often delayed and difficult to quantify, requiring data on lifetime reproduction. Here, we use a longitudinal dataset to examine the lifetime reproductive success of cooperative polygamy in acorn woodpeckers (), which nest as lone pairs or share reproduction with same-sex cobreeders. We found that males and females produced fewer young per successful nesting attempt when sharing reproduction. However, males nesting in duos and trios had longer reproductive lifespans, more lifetime nesting attempts and higher lifetime reproductive success than those breeding alone. For females, cobreeding in duos increased reproductive lifespan so the lifetime reproductive success of females nesting in duos was comparable to those nesting alone and higher than those nesting in trios. These results suggest that for male duos and trios, reproductive success alone may provide sufficient fitness benefits to explain the presence of cooperative polygamy, and the benefits of cobreeding as a duo in females are higher than previously assumed. Lifetime individual fitness data are crucial to reveal the full costs and benefits of cooperative polygamy.
当个体放弃繁殖或分享繁殖机会时，合作繁殖策略会导致短期的直接适合度损失。合作策略的直接适合度益处往往延迟出现且难以量化，这需要关于终生繁殖的数据。在此，我们使用一个纵向数据集来研究橡树啄木鸟合作多配偶制的终生繁殖成功率，这些啄木鸟要么成对筑巢，要么与同性共同繁殖者分享繁殖机会。我们发现，在分享繁殖机会时，雄性和雌性每次成功筑巢尝试所育幼鸟数量较少。然而，成对和三人组筑巢的雄性比单独繁殖的雄性具有更长的繁殖寿命、更多的终生筑巢尝试次数以及更高的终生繁殖成功率。对于雌性而言，成对共同繁殖会延长繁殖寿命，因此成对筑巢的雌性的终生繁殖成功率与单独筑巢的雌性相当，且高于三人组筑巢的雌性。这些结果表明，对于雄性二人组和三人组来说，仅繁殖成功率可能就提供了足够的适合度益处来解释合作多配偶制的存在，并且雌性作为二人组共同繁殖的益处比之前所认为的更高。终生个体适合度数据对于揭示合作多配偶制的全部成本和益处至关重要。
