Eichenberger Franca, Carroll Emma L, Garrigue Claire, Steel Debbie J, Bonneville Claire D, Rendell Luke, Garland Ellen C
Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK.
School of Biological Sciences, University of Auckland - Waipapa Taumata Rau, Auckland, New Zealand.
R Soc Open Sci. 2025 Jan 8;12(1):241424. doi: 10.1098/rsos.241424. eCollection 2025 Jan.
Variation in reproductive success is a fundamental prerequisite for sexual selection to act upon a trait. Assessing such variation is crucial in understanding a species' mating system and offers insights into population growth. Parentage analyses in cetaceans are rare, and the underlying forces of sexual selection acting on their mating behaviours remain poorly understood. Here, we combined 25 years of photo-identification and genetic data to assess patterns of male reproductive success and reproductive autonomy of the New Caledonian (Oceania, South Pacific) humpback whale breeding population. Paternity analysis of 177 mother-offspring pairs and 936 males revealed low variation in male reproductive success (average 1.17 offspring per father) relative to other polygynous species. The observed skew in success was higher than expected under random mating and skewed overall towards males (93%) without evidence of paternity over the study period. Finally, an updated male gametic mark-recapture abundance estimate of 2084 (95% confidence interval = 1761-2407, 1995-2019) fell between previous census estimates of the New Caledonian population and the wider Oceanian metapopulation. Our results provide critical insights into the mating competition of male humpback whales and population dynamics across Oceanian populations, two important factors affecting the slow recovery from whaling across the South Pacific region.
繁殖成功率的差异是性选择作用于某一性状的基本前提。评估这种差异对于理解一个物种的交配系统至关重要，并能为种群增长提供见解。鲸类动物的亲权分析很少见，对其交配行为起作用的性选择潜在力量仍知之甚少。在这里，我们结合了25年的照片识别和遗传数据，以评估新喀里多尼亚（大洋洲，南太平洋）座头鲸繁殖种群中雄性的繁殖成功率模式和繁殖自主性。对177对母-子对和936头雄性进行的父权分析显示，相对于其他一夫多妻制物种，雄性繁殖成功率的差异较低（平均每位父亲有1.17个后代）。在随机交配情况下，观察到的成功偏差高于预期，且总体上偏向雄性（93%），在研究期间没有父权证据。最后，更新后的雄性配子标记重捕丰度估计值为2084（95%置信区间 = 1761 - 2407，1995 - 2019），介于新喀里多尼亚种群和更广泛的大洋洲复合种群之前的普查估计值之间。我们的研究结果为雄性座头鲸的交配竞争以及大洋洲各种群的种群动态提供了关键见解，这两个重要因素影响着整个南太平洋地区捕鲸后缓慢的恢复过程。
