Environmental drivers of sexual dimorphism in a lizard with alternative mating strategies. (25th June 2021)

• Record Type: Journal Article
• Authors: Chelini, Marie Claire; Brock, Kinsey; Yeager, Justin; Edwards, Danielle L.
• Is Part Of: Journal of evolutionary biology. Volume 34:Number 8(2021)
• Page Start: 1241
• Page End: 1255
• Publication Date: 2021-06-25
• Subjects: polymorphism -- reverse Bergmann cline -- side‐blotched lizard -- SSD -- temperature‐size rule -- Uta stansburiana; Evolution (Biology) -- Periodicals; Biology -- Periodicals; 576.8
• DOI: 10.1111/jeb.13881
• Languages: English
• ISSNs: 1010-061X

Abstract

Abstract: Understanding the relative importance of sexual and natural selection in shaping morphological traits is a long‐standing goal of evolutionary ecology. Male‐biased sexual size dimorphism (SSD) is typically associated with male–male competition. Similarly, male polymorphisms are considered a consequence of competitive social interactions. This classic paradigm overlooks the fact that environmental factors mediate social interactions and can lead to ecological adaptations. Common side‐blotched lizards, Uta stansburiana, are a model system for this paradigm due to well‐known rock‐paper‐scissors social dynamics between male morphs. SSD in this species has been considered primarily a consequence of social interactions, with male size resulting from the number of morphs in each population and female size being constrained through fecundity benefits. We test if the environment explains intraspecific variation in SSD and number of male morphs in U. stansburiana . By compiling data from 49 populations, we show that environmental variables are stronger predictors of SSD than the number of male morphs. Similarly, we show that the environment mediates SSD and potentially contributes to morph loss in colder environments. We propose that the environment favours smaller males in areas of high seasonality. Our results demonstrate the importance of the environment as a mediator of SSD. Abstract : Using phylogenetic path analyses and regression models, we disentangle the relationship between color polymorphisms and sexual size dimorphism in the side‐blotched lizard Uta stansburiana, and demonstrate the role played by the abiotic environment in the variation observed in sexually selected traits across populations.