Parejo Deseada, González-Medina Erick, Cruz-Miralles Ángel, Avilés Jesús Miguel
Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería, Spain.
Unidad Asociada (CSIC-UEX): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain.
Sci Rep. 2025 Jun 2;15(1):19312. doi: 10.1038/s41598-025-04191-1.
The persistence of color polymorphism in nature may be driven by disassortative mating based on color. In vertebrates, body size sometimes correlates with coloration, complicating mating patterns, as the selective pressures favoring mixed-color pairs might be counterbalanced by those influencing body size. This complexity is heightened in species with reversed sexual size dimorphism, such as owls, where males are smaller than females, and average dissimilarity in mate size may reflect sexual size dimorphism rather than an active disassortative mating pattern. Here we investigate the fitness consequences of mating by color and body size using a long-term dataset from the color polymorphic Eurasian Scops owl (Otus scops), a bird species with reversed sexual size dimorphism. Results reveal that size-disassortative mating enhances reproductive success, as highly size-dimorphic pairs have higher probability of fledging owlets, which may favor reversed sexual size dimorphism. In addition, larger pairs produce heavier owlets with higher immunocompetence, aligning with the conventional size-based mating hypothesis. Although body size and plumage coloration were correlated within pairs, only differences in body size between pair members, not coloration, were related to higher fitness estimates. While color-based assortative mating had no direct impact on any of the fitness proxies studied, greyer pairs exhibited higher feeding rates to offspring than browner pairs. These results underscore the importance of simultaneously considering traits that may covary with color and shape mating patterns to understand the persistence of color polymorphisms in nature.
自然界中颜色多态性的持续存在可能是由基于颜色的异交驱动的。在脊椎动物中，体型有时与体色相关，这使交配模式变得复杂，因为有利于混合颜色配对的选择压力可能会被影响体型的选择压力所抵消。在具有性大小反转二态性的物种中，这种复杂性会加剧，比如猫头鹰，雄性比雌性小，配偶体型的平均差异可能反映的是性大小二态性，而不是一种主动的异交交配模式。在这里，我们利用来自颜色多态的欧亚角鸮（Otus scops）的长期数据集，研究了按颜色和体型交配的适应性后果，欧亚角鸮是一种具有性大小反转二态性的鸟类。结果表明，体型异交交配能提高繁殖成功率，因为体型差异大的配对有更高的概率使雏鸟成功 fledging，这可能有利于性大小反转二态性。此外，体型较大的配对会产出免疫能力更强、体重更重的雏鸟，这与传统基于体型的交配假说相符。尽管配对个体间的体型和羽毛颜色存在相关性，但只有配对成员间的体型差异，而非颜色差异，与更高的适应性估计值相关。虽然基于颜色的同型交配对所研究的任何适应性指标都没有直接影响，但体色较灰的配对比体色较棕的配对对后代的喂食率更高。这些结果强调了在理解自然界中颜色多态性的持续存在时，同时考虑可能与颜色和体型交配模式相关的性状的重要性。
