Dietary stress increases the total opportunity for sexual selection and modifies selection on condition‐dependent traits. (15th December 2019)

• Record Type: Journal Article
• Authors: Cattelan, Silvia; Evans, Jonathan P.; Garcia‐Gonzalez, Francisco; Morbiato, Elisa; Pilastro, Andrea
• Editors: Ghalambor, Cameron
• Is Part Of: Ecology letters. Volume 23:Number 3(2020)
• Page Start: 447
• Page End: 456
• Publication Date: 2019-12-15
• Subjects: Adaptation -- condition‐dependence -- environmental change -- opportunity of selection -- sexually selected traits -- total sexual selection; Ecology -- Periodicals; 577
• DOI: 10.1111/ele.13443
• Languages: English
• ISSNs: 1461-023X

Abstract

Abstract: Although it is often expected that adverse environmental conditions depress the expression of condition‐dependent sexually selected traits, the full consequences of environmental change for the action of sexual selection, in terms of the opportunity for total sexual selection and patterns of phenotypic selection, are unknown. Here we show that dietary stress in guppies, Poecilia reticulata, reduces the expression of several sexually selected traits and increases the opportunity for total sexual selection (standardized variance in reproductive success) in males. Furthermore, our results show that dietary stress modulates the relative importance of precopulatory (mating success) and postcopulatory (relative fertilization success) sexual selection, and that the form of multivariate sexual selection (linear vs. nonlinear) depends on dietary regime. Overall, our results are consistent with a pattern of heightened directional selection on condition‐dependent sexually selected traits under environmental stress, and underscore the importance of sexual selection in shaping adaptation in a changing world. Abstract : Theory predicts that variance in male reproductive success, and therefore the opportunity for sexual selection, will increase when males encounter stressful environmental conditions that impact the expression of condition‐dependent sexually selected traits. Despite the simplicity of this prediction, the extent to which environmental factors influence the strength, direction and patterns of sexual selection has never been tested. Here, we show that in guppies, an iconic model for sexual selection research, dietary stress increases variance in male reproductive success, changes the relative contribution of pre‐ and post‐copulatory components of sexual selection, and causes a dramatic shift in patterns of multivariate sexual selection. These findings highlight the importance of considering environmental heterogeneity when characterising sexual selection.