Reduced sexual size dimorphism in a pipefish population where males do not prefer larger females.

Autor: Cunha M; CIBIO/InBIO Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto Vairão Portugal., Macedo N; CIBIO/InBIO Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto Vairão Portugal., Wilson J; CIIMAR Centro Interdisciplinar de Investigação Marinha e Ambiental Universidade do Porto Porto Portugal.; Wilfrid Laurier University Waterloo Ontario Canada., Rosenqvist G; Department of Biology CBD, NTNU Trondheim Norway.; Department of Earth Sciences Blue Centre Gotland Uppsala University Uppsala Sweden., Berglund A; Department of Ecology and Genetics/Animal Ecology Uppsala University Uppsala Sweden., Monteiro N; CIBIO/InBIO Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto Vairão Portugal.; Departamento de Biologia Faculdade de Ciências da Universidade do Porto Porto Portugal.; Faculdade de Ciências da Saúde CEBIMED Universidade Fernando Pessoa Porto Portugal.
Jazyk: angličtina
Zdroj: Ecology and evolution [Ecol Evol] 2019 Nov 01; Vol. 9 (22), pp. 12826-12835. Date of Electronic Publication: 2019 Nov 01 (Print Publication: 2019).
DOI: 10.1002/ece3.5760
Abstrakt: Within a species' distribution, populations are often exposed to diverse environments and may thus experience different sources of both natural and sexual selection. These differences are likely to impact the balance between costs and benefits to individuals seeking reproduction, thus entailing evolutionary repercussions. Here, we look into an unusual population (Baltic Sea) of the broadnosed pipefish, Syngnathus typhle , where males do not seem to select females based on size and hypothesize that this pattern may derive from a reduction in direct benefits to the male. We further hypothesize that if larger females do not persistently secure a higher reproductive success, either through pre- or postcopulatory sexual selection, a decrease in sexual size dimorphism in the Baltic population should be apparent, especially when contrasted with a well-studied population, inhabiting similar latitudes (Swedish west coast), where males prefer larger females. We found that, in the Baltic population, variation in female quality is low. We were unable to find differences in abortion rates or protein concentration in oocytes produced by females of contrasting sizes. Direct benefits from mating with large partners seem, thus, reduced in the Baltic population. We also found no evidence of any postcopulatory mechanism that could favor larger mothers as embryo development was unrelated to female size. While female size can still be selected through intrasexual competition or fecundity selection, the pressure for large female body size seems to be lower in the Baltic. Accordingly, we found a noticeable decrease in sexual size dimorphism in the Baltic population. We conclude that, although far from negating the significance of other selective processes, sexual selection seems to have a decisive role in supporting pipefish sexual size asymmetries.
Competing Interests: The authors declare no competing interest.
(© 2019 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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