<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Sexual selection may impose fitness costs on both males and females due to the costs of developing and maintaining exaggerated sexual signals, reducing average fitness in strongly sexually selected species. Such reductions in average fitness could affect local extinction risk and hence distribution range. However, given that both sexually monochromatic and dichromatic species are common and widespread, benefits of sexual selection must be invoked to maintain equilibrium. We tested for differences in breeding range size and population size between monochromatic and dichromatic species of birds in a comparative analysis of species from the Western Palaearctic. In an analysis of standardized linear contrasts of the relationship between sexual dichromatism and range size and population size, respectively, that controlled for similarity among taxa due to common descent, we found no significant relationship. However, when we analyzed carotenoid-based sexual dichromatism sexually dichromatic species had larger distribution areas and higher northernmost distribution limits, but not southernmost distribution limits than sexually monochromatic species. In contrast, melanin-based sexual dichromatism was not significantly associated with range size or population size. Therefore, population density of sexually dichromatic species with carotenoid-based coloration was lower than that of monochromatic species, because dichromatic species had similar population sizes but larger ranges than monochromatic species. These findings suggest that the different physiological roles of pigments associated with sexual dichromatism have effects on total range size of birds.</p></abstract>

Sexual selection may impose fitness costs on both males and females due to the costs of developing and maintaining exaggerated sexual signals, reducing average fitness in strongly sexually selected species. Such reductions in average fitness could affect local extinction risk and hence distribution range. However, given that both sexually monochromatic and dichromatic species are common and widespread, benefits of sexual selection must be invoked to maintain equilibrium. We tested for differences in breeding range size and population size between monochromatic and dichromatic species of birds in a comparative analysis of species from the Western Palaearctic. In an analysis of standardized linear contrasts of the relationship between sexual dichromatism and range size and population size, respectively, that controlled for similarity among taxa due to common descent, we found no significant relationship. However, when we analyzed carotenoid-based sexual dichromatism sexually dichromatic species had larger distribution areas and higher northernmost distribution limits, but not southernmost distribution limits than sexually monochromatic species. In contrast, melanin-based sexual dichromatism was not significantly associated with range size or population size. Therefore, population density of sexually dichromatic species with carotenoid-based coloration was lower than that of monochromatic species, because dichromatic species had similar population sizes but larger ranges than monochromatic species. These findings suggest that the different physiological roles of pigments associated with sexual dichromatism have effects on total range size of birds.

Sexual selection, range size and population size

Laboratoire d’Ecologie, Systematique et Evolution, Université Paris-Sud, Orsay France

Department of Evolutionary Ecology, Estacion Biologica de Donana-CSIC, Seville, Spain

Ornis Hungarica

{"article-title":"Sexual selection, range size and population size"}

Sexual selection may impose fitness costs on both males and females due to the costs of developing and maintaining exaggerated sexual signals, reducing average...

Sexual selection, range size and population size

Online veröffentlicht: 08. Okt. 2013

Seitenbereich: 1 - 25

DOI: https://doi.org/10.2478/orhu-2013-0001

Schlüsselwörter
birds, carotenoids, melanin, sexual dichromatism, sexual selection

This content is open access.

Sexual selection, range size and population size

Online veröffentlicht: 08. Okt. 2013

Seitenbereich: 1 - 25

DOI: https://doi.org/10.2478/orhu-2013-0001

Schlüsselwörterbirds, carotenoids, melanin, sexual dichromatism, sexual selection

This content is open access.

Schlüsselwörter
birds, carotenoids, melanin, sexual dichromatism, sexual selection