Sexual size dimorphism in anurans: roles of mating system and habitat types

Wen Bo Liao,Jian Dong Yang,Yu Zeng

doi:10.1186/1742-9994-10-65

Abstract

BackgroundSexual size dimorphism (SSD) is widespread and variable among animals. Sexual selection, fecundity selection and ecological divergence between males and females are the major evolutionary forces of SSD. However, the influences of mating system and habitat types on SSD have received little attention. Here, using phylogenetic comparative methods, we at first examine the hypotheses to that mating system (intensity of sexual selection) and habitat types affect significantly variation in SSD in anurans (39 species and 18 genera).ResultsOur data set encompass 39 species with female-biased SSD. We provide evidence that the effects of mating system and habitat types on SSD were non-significant across species, also when the analyses were phylogenetically corrected.ConclusionsContrast to the hypotheses, our findings suggest that mating system and habitat types do not play an important role in shaping macro-evolutionary patterns of SSD in anurans. Mating system and habitat types cannot explain the variation in SSD when correcting for phylogenetic effects.

Highlights

Sexual size dimorphism (SSD) is widespread and variable among animals [1]
It is widely agreed that sexual selection in favor of large males to improve intra-sexual combat success and fecundity selection for large females to increase reproductive output are the major evolutionary forces of SSD in many organisms [1]
We found the mean SVL contrasts significantly differed between the sexes (F1, 75 = 3.182, P = 0.041) and habitats (F3, 75 = 4.342, P = 0.020), but did not differ among mating system (F2, 75 = 0.038, P = 0.963)

Summary

Introduction

Sexual size dimorphism (SSD) is widespread and variable among animals [1]. In some groups (e.g. birds, lizards and most mammals), males are bigger than females, whereas in other groups (fishes and anurans) females are bigger than males [2]. If the selection hypotheses are valid, we expect mating system and habitat types having effects on SSD in anurans. The influences of mating system and habitat types on SSD in anurans have received little attention. We at first examine the hypotheses to that mating system and habitat types significantly influence on variation of SSD. Fecundity selection and ecological divergence between males and females are the major evolutionary forces of SSD. The influences of mating system and habitat types on SSD have received little attention. Using phylogenetic comparative methods, we at first examine the hypotheses to that mating system (intensity of sexual selection) and habitat types affect significantly variation in SSD in anurans (39 species and 18 genera)

Methods

Results

Conclusion