Consequences of sexual selection within and between species of phyllostomid bats

Loading...
Thumbnail Image

Files

Publication or External Link

Date

2019

Citation

Abstract

To understand the myriad effects of sexual selection in the evolution and diversification of life, we must investigate variation within and among diverse animal taxa. Here, I study sexual selection in phyllostomid bats (Family Phyllostomidae), a diverse radiation comprised of 216 species that vary widely in their social behavior and roosting ecology, but whose mating behavior is largely unknown. First, I investigate whether socio-ecological traits predict variation in the intensity of sexual selection among phyllostomid species. In the absence of behavioral data, I use measures of sexual dimorphism as an indicator of precopulatory sexual selection and testes size as a proxy for postcopulatory competition. Taking a phylogenetic approach, I find that roosting aggregation size, but not roost structure permanence, explains family-wide variation in both pre- and postcopulatory sexual selection. Next, I examine the distribution of extra-group paternity in a single species, Phyllostomus hastatus, whose social mating system of female-defense polygyny has been well described. Through molecular parentage assignment of 241 offspring from three wild colonies in Trinidad, West Indies, I find that most harem-holding males are unable to monopolize mating in their social groups, resulting in paternity by extra-group males. Furthermore, variation in the rate of extra-group paternity is associated with harem male body condition as well as the composition of the female group. Finally, I investigate the variation in a male-specific chemical signal found in P. hastatus, which has been implicated in male-male competition and female choice of this species. Results show that in addition to individual variation, harem males have significantly different chemical profiles from males found roosting in all-male groups (bachelors). Through the examination of both family-wide and species-specific patterns, we can broaden our understanding of how sexual selection has contributed to the diversity within the Phyllostomidae.

Notes

Rights