Bain Glen C, Hall Michelle L, Mulder Raoul A
Department of Zoology, University of Melbourne, Melbourne, Vic., 3010, Australia.
Mol Ecol. 2014 Nov;23(22):5619-27. doi: 10.1111/mec.12959. Epub 2014 Nov 4.
The frequency of extra-pair paternity (EPP) in socially monogamous birds varies substantially between and within species, but ecological drivers of this variation remain poorly understood. Habitat configuration could influence EPP by moderating access to extra-pair mates, because species occupying territories in a clustered 'honeycomb' configuration have a larger pool of potential extra-group mates in their immediate neighbourhood than those living in linearly arranged territories (e.g. along narrow strips of riparian or fragmented habitat). We exploited variation in the spatial arrangement of territories due to anthropogenic modification of habitat of the cooperatively breeding superb fairy-wren Malurus cyaneus to test whether habitat configuration influenced the frequency of EPP. In this species, most paternity is obtained by males outside the social group [extra-group paternity (EGP)]. We found that the frequency of EGP among groups living in linear strips of roadside vegetation (41% of 44 offspring) was lower than it was for groups living in clustered territories within continuous habitat (59% of 70 offspring). Differences in group size and pair relatedness did not explain differences in EGP associated with territory configuration, although the frequency of EGP was negatively correlated with pair relatedness. Our finding suggests that territory configuration can influence rates of EGP and that anthropogenic habitat fragmentation has the potential to limit access to extra-pair mates, affecting mating systems and ultimately fitness.
在社会性一夫一妻制鸟类中，婚外父权（EPP）的频率在不同物种之间以及同一物种内部都有很大差异，但这种差异的生态驱动因素仍知之甚少。栖息地配置可能通过调节与婚外配偶的接触来影响婚外父权，因为占据呈集群状“蜂巢”配置领地的物种，其紧邻区域内潜在的群体外配偶池比生活在呈线性排列领地（如沿着狭窄的河岸带或破碎栖息地）的物种更大。我们利用了由于对合作繁殖的华丽细尾鹩莺（Malurus cyaneus）栖息地进行人为改造而导致的领地空间排列变化，来测试栖息地配置是否会影响婚外父权的频率。在这个物种中，大多数父权是由社会群体之外的雄性获得的[群体外父权（EGP）]。我们发现，生活在路边植被线性条带中的群体的群体外父权频率（44只后代中的41%）低于生活在连续栖息地中集群领地的群体（70只后代中的59%）。群体大小和配偶亲缘关系的差异并不能解释与领地配置相关的群体外父权差异，尽管群体外父权频率与配偶亲缘关系呈负相关。我们研究结果表明，领地配置会影响群体外父权率，人为造成的栖息地破碎化有可能限制与婚外配偶的接触，影响交配系统并最终影响适合度。
