Climatic conditions cause spatially dynamic polygyny thresholds in a large mammal

The polygyny threshold (PT) is a critical transition point in the sexual selection process for many organisms in natural populations, characterizing when females choose to mate with an already mated male over an unmated one to improve fitness. Understanding its causes and consequences is therefore of high interest. While both theoretical and empirical work suggest that the degree of polygyny within a species is plastic and a function of male inequality, the functional relationship between underlying availability of resources occupied by breeding males under variable climatic conditions and the dynamics of PTs across space and time has received less attention.
Here, we use a standardized measure of male mating inequality as the culmination of female mate choices to analyse how spatially dynamic PTs in a naturally regulated feral horse (Equus ferus caballus) population emerge along a geographic gradient in a known, limiting resource (freshwater) each year from variable climatic condition...

一妻多夫阈值（polygyny threshold, PT）是自然种群中众多生物的性选择过程里的关键转折点，用于描述雌性为提升自身适合度（fitness），为何会选择与已交配雄性而非未交配雄性进行交配的临界条件。因此，探明该阈值的成因与影响，具有重要的研究价值。尽管理论与实证研究均表明，物种种内的一妻多夫程度具有可塑性，且与雄性间的不平等程度相关，但在多变气候条件下，繁殖雄性所占据的潜在资源可获得性，与一妻多夫阈值随空间和时间的动态变化之间的功能联系，却尚未得到足够关注。
本研究采用雄性配偶不平等程度的标准化测度指标，将其作为雌性配偶选择的最终结果，以分析在受自然调控的野化家马（Equus ferus caballus）种群中，具有空间动态性的一妻多夫阈值，如何每年在多变气候条件下，沿已知限制性资源（淡水）的地理梯度逐步形成……