RT Journal Article
T1 Size, not color, drives assortative mating and influences fledging survival, weight and immunity in a polymorphic owl
A1 Parejo, Deseada
A1 González Medina, Erick
A1 Cruz Miralles, Ángel
A1 Avilés, Jesús Miguel
AB 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.
PB Springer Nature
SN 2045-2322
YR 2025
FD 2025-06-02
LK https://hdl.handle.net/20.500.14352/122596
UL https://hdl.handle.net/20.500.14352/122596
LA eng
NO Parejo, D., González-Medina, E., Cruz-Miralles, Á., & Avilés, J. M. (2025). Size, not color, drives assortative mating and influences fledging survival, weight and immunity in a polymorphic owl. Scientific Reports, 15(1). https://doi.org/10.1038/S41598-025-04191-1
NO The study was funded by the Spanish Ministries of Education and Science/FEDER and of Economy, Industry and Competitiveness, respectively, through the projects CGL2014-56769-P, CGL2017-83503-P and PID2020-119576GB-I00.
NO Ministerio de Ciencia e Innovación  (España)
NO European Commission
NO Ministerio de Economía, Industria y Competitividad (España
DS Docta Complutense
RD 18 dic 2025