Brekke Patricia, Ewen John G, Clucas Gemma, Santure Anna W
Institute of Zoology, Zoological Society of London Regents Park, London, UK.
Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus European Way, Southampton, UK.
Evol Appl. 2015 Sep;8(8):796-806. doi: 10.1111/eva.12287. Epub 2015 Jul 28.
Floating males are usually thought of as nonbreeders. However, some floating individuals are able to reproduce through extra-pair copulations. Floater reproductive success can impact breeders' sex ratio, reproductive variance, multiple paternity and inbreeding, particularly in small populations. Changes in reproductive variance alter the rate of genetic drift and loss of genetic diversity. Therefore, genetic management of threatened species requires an understanding of floater reproduction and determinants of floating behaviour to effectively conserve species. Here, we used a pedigreed, free-living population of the endangered New Zealand hihi (Notiomystis cincta) to assess variance in male reproductive success and test the genetic (inbreeding and heritability) and conditional (age and size) factors that influence floater behaviour and reproduction. Floater reproduction is common in this species. However, floater individuals have lower reproductive success and variance in reproductive success than territorial males (total and extra-pair fledglings), so their relative impact on the population's reproductive performance is low. Whether an individual becomes a floater, and if so then how successful they are, is determined mainly by individual age (young and old) and to lesser extents male size (small) and inbreeding level (inbred). Floating males have a small, but important role in population reproduction and persistence of threatened populations.
漂泊雄性通常被认为是不繁殖的个体。然而，一些漂泊个体能够通过配偶外交配进行繁殖。漂泊者的繁殖成功会影响繁殖者的性别比例、繁殖方差、多重父权和近亲繁殖，特别是在小种群中。繁殖方差的变化会改变遗传漂变的速率和遗传多样性的丧失。因此，对濒危物种进行遗传管理需要了解漂泊者的繁殖情况以及漂泊行为的决定因素，以便有效地保护物种。在此，我们利用一个有谱系记录的、自由生活的濒危新西兰吸蜜鸟（Notiomystis cincta）种群，来评估雄性繁殖成功率的方差，并测试影响漂泊行为和繁殖的遗传因素（近亲繁殖和遗传力）以及条件因素（年龄和体型）。漂泊者繁殖在该物种中很常见。然而，漂泊个体的繁殖成功率和繁殖成功方差低于领地雄性（包括总雏鸟和配偶外雏鸟），因此它们对种群繁殖表现的相对影响较低。一个个体是否成为漂泊者，以及如果成为漂泊者其成功程度如何，主要由个体年龄（年轻和年老）决定，在较小程度上由雄性体型（小）和近亲繁殖水平（近亲繁殖）决定。漂泊雄性在种群繁殖和濒危种群的存续中发挥着虽小但重要的作用。
