Authors: Vanessa Kellermann, Johannes Overgaard, Carla M Sgrò, and Ary A Hoffmann

Published in: Journal of Evolutionary Biology

Abstract

Sex-based differences in physiological traits may be influenced by both evolutionary and environmental factors.

Here we used male and female flies from >80 Drosophila species reared under common conditions to examine variance in a number of physiological traits including size, starvation, desiccation and thermal tolerance.

Sex-based differences for desiccation and starvation resistance were comparable in magnitude to those for size, with females tending to be relatively more resistant than males. In contrast thermal resistance showed low divergence between the sexes.

Phylogenetic signal was detected for measures of divergence between the sexes, such that species from the Sophophora clade showed larger differences between the sexes than species from the Drosophila clade.

We also found that sex-based differences in desiccation resistance, body size and starvation resistance were weakly associated with climate (annual mean temperature/precipitation seasonality) but the direction and association with environment depended on phylogenetic position.

The results suggest that divergence between the sexes can be linked to environmental factors, while an association with phylogeny suggests sex-based differences persist over long evolutionary time-frames.

Phylogenetic analysis of sex-based differences in desiccation resistance, starvation resistance and body size. Top: Phylogenetic hypothesis of the Drosophila species examined and their sub-groups. Bottom: Sex-based differences mapped onto the phylogeny via ancestral trait reconstruction for continuous characters for traits desiccation resistance (left), body size (middle) and starvation resistance (right). Bars represent the average sexual dimorphism index for each trait, with dots above the bars indicating a significant difference between the sexes when analysed with a one-way ANOVA.

Citation

Kellermann V, Overgaard J, Sgrò CM, Hoffmann AA (2022) Phylogenetic and environmental patterns of sex differentiation in physiological traits across Drosophila species. Journal of Evolutionary Biology PDF DOI