Differential responses to related hosts by nesting and non-nesting parasites in a brood-parasitic duck

Host-parasite relatedness may facilitate the evolution of conspecific brood parasitism (CBP), but empirical support for this contention remains inconclusive. One reason for this disparity may relate to the diversity of parasitic tactics, a key distinguishing feature being whether the parasite has a nest of her own. Previous work suggests that parasites without nests of their own may be of inferior phenotypic quality, but due to difficulties in identifying these parasitic individuals, little is known about their host selection criteria. We used high-resolution molecular maternity tests to assign parasitic offspring to known parasites with and without their own nests in a population of Barrow’s goldeneyes (Bucephala islandica). We determined whether parasite nesting status, host-parasite relatedness, and distance between host and parasite nests affected the probability of parasitizing a host and the number of eggs laid per host. We also investigated whether nesting parasites, conventional...宿主与寄生物的亲缘关系或可促进种内巢寄生（conspecific brood parasitism, CBP）的演化，但目前针对这一论点的实验证据尚未得出定论。造成这一研究分歧的原因之一，可能与寄生策略的多样性有关，其中一项核心区分特征为寄生物是否拥有自身的巢穴。既往研究表明，无自有巢穴的寄生物表型质量较差，但由于难以识别这类寄生个体，学界对其宿主选择标准仍知之甚少。本研究采用高分辨率分子母本鉴定技术，在巴氏鹊鸭（Bucephala islandica）种群中，将寄生后代归属于已知的有自有巢穴和无自有巢穴的寄生物个体。我们分析了寄生物的筑巢状态、宿主-寄生物亲缘关系以及宿主与寄生物巢穴间的距离，是否会影响宿主被寄生的概率以及单个宿主的产卵量。我们还针对有自有巢穴的寄生物、常规……展开了研究。