LTREB: Ecology and Evolution of Cooperative Breeding

合作育种的生态学和进化PI：沃尔特D。橡子啄木鸟（Melanerpes formicivorus）是加州的一种常见鸟类，它表现出任何脊椎动物中最复杂的社会行为。群体组成包括从一个简单的繁殖对到包含多达7个共享繁殖状态的雄性（共育），3个在同一个巢腔中产卵的雌性（联合巢），以及可变数量的非繁殖助手（繁殖者的后代）的群体。先前的研究表明，多达3只雄性和3只雌性可能对一个巢穴的遗传做出贡献。这些个体中的一个在一个群体中垄断亲子关系的程度，被称为“生殖偏斜”，在联合筑巢的雌性中很低，但在共育雄性中很高。也就是说，在一个巢中，一只雄性通常会生下所有或几乎所有的幼崽。这种高度的繁殖倾斜之间的共育男性是预测由目前的理论给出了明显的优势，生活在群体和困难离开一个群体，去自己的。通过比较父子关系在第一和第二巢的群体与2 cobreeder男性，该提案将测试备择假设，即cobreeder男性有平等的机会繁殖后代，但亲子关系的个别年轻人在一个育雏是一个“全或无”的现象，而不是独立确定每个雏鸟。如果是这样的话，这就意味着控制父权的是雌性，而不是一个共育的雄性，这与生殖偏斜理论的一个主要假设相反。该提案还将通过检查包含3个或更多共育雄性的组以及具有共育雄性和联合筑巢雌性的组中的行为和亲子关系来扩展先前的结果。

LTREB: Ecology and evolution of cooperative breedingPI: Walter D. Koenig The acorn woodpecker (Melanerpes formicivorus) is a common bird in California that exhibits some of the most complex social behavior of any vertebrate. Group composition consists of anything from a simple breeding pair to groups containing up to 7 males sharing breeding status (cobreeders), 3 females laying eggs in the same nest cavity (joint-nesters), and a variable number of nonbreeding helpers that are offspring of the breeders from prior years. Prior work has revealed that up to 3 males and 3 females may contribute genetically to a single nest. The degree to which one of these individuals monopolizes parentage within a group, known as "reproductive skew", is low among joint-nesting females but high among cobreeder males. That is, within a nest, one male usually sires all or nearly all the young. This high degree of reproductive skew among cobreeder males is predicted by current theory given the apparent advantages to living in groups and the difficulty of leaving a group and going off on one's own. By comparing paternity in first and second nests of groups with 2 cobreeder males, the proposal will test the alternative hypothesis that cobreeder males have equal chance of siring young, but that paternity of individual young within a brood is an "all or none" phenomenon rather than independently determined for each nestling. If so, this would imply that females, rather than one of the cobreeder males, are in control of paternity, counter to a major assumption of reproductive skew theory. The proposal will also extend prior results by examining behavior and paternity in groups containing 3 or more cobreeder males and in groups with both cobreeder males and joint-nesting females.