Data from: Relatedness and spatial proximity as determinants of host-parasite interactions in the brood parasitic Barrow's goldeneye (Bucephala islandica)

Recent studies which have found evidence for kin-biased egg donation have sparked interest in re-assessing the parasitic nature of conspecific brood parasitism (CBP). Since host-parasite kinship is essential for mutual benefits to arise from CBP, we explored the role of relatedness in determining the behaviour of conspecific nest parasites and their hosts in nesting female Barrow's goldeneyes (Bucephala islandica), a duck in which CBP is common. The results revealed that the amount of parasitism increased with host-parasite relatedness, the effect of which was independent of geographic proximity of host and parasite nests. Proximity per se was also positively associated with the amount of parasitism. Furthermore, while hosts appeared to reduce their clutch size as a response to the presence of parasitic eggs, the magnitude of host clutch reduction also tended to increase with increasing relatedness to the parasite. Hence, our results indicate that both relatedness and spatial proximity are important determinants of CBP, and that host clutch reduction may be an adaptation to nest parasitism, modulated by host-parasite relatedness. Taken together, the results provide a demonstration that relatedness influences host and parasite behaviour in Barrow's goldeneyes, resulting in kin-biased egg donation.

近期有研究发现了亲缘偏向性寄卵行为的相关证据，这引发了学界重新评估种内巢寄生（conspecific brood parasitism, 简称CBP）本质的研究兴趣。由于寄主与寄生物的亲缘关系是种内巢寄生产生互利关系的必要前提，本研究以种内巢寄生现象较为普遍的鸭类——巴罗金眼鸭（Bucephala islandica）的筑巢雌性个体为研究对象，探究了亲缘关系在决定种内巢寄生物及其寄主行为中的作用。研究结果显示，寄卵总量随寄主与寄生物间亲缘关系的增强而升高，且该效应不受二者巢穴地理间距的影响。巢穴间距本身也与寄卵量呈显著正相关。此外，尽管寄主会因寄生产卵的存在而缩减自身窝卵数，但其窝卵数的缩减幅度也随与寄生物亲缘关系的提升而呈增大趋势。因此，本研究结果表明，亲缘关系与空间距离均为种内巢寄生的重要影响因素，且寄主缩减窝卵数或为应对巢寄生的适应性策略，其强度受寄主与寄生物间亲缘关系的调控。综合来看，本研究结果证实了亲缘关系会影响巴罗金眼鸭的寄主与寄生物行为，进而产生亲缘偏向性寄卵行为。