The adaptive maintenance of phenotypic polymorphism

This is a Preprint and has not been peer reviewed. This is version 2 of this Preprint. You must log in to post a comment. There are no comments or no comments have been made public for this article. This is a Preprint and has not been peer reviewed. This is version 2 of this Preprint. Add a Comment You must log in to post a comment. Comments There are no comments or no comments have been made public for this article. Phenotypic polymorphisms have fascinated evolutionary biologists since the field’s inception, providing easily observable and quantifiable variation amenable to both empirical and theoretical study. However, a clear method for developing alternative hypotheses for the adaptive processes by which multiple morphs are maintained remains elusive. Here we review hypotheses for the maintenance of polymorphisms and propose a framework in which polymorphisms can be described by (i) a type of balancing selection and (ii) the ecological and social context through which balancing selection acts. We argue that a complete hypothesis for the maintenance of polymorphism should describe both variables, offering a simple method for generating testable alternatives. To demonstrate this, we explore the case of female-limited polymorphism, a class of polymorphisms with diverse explanations, yet little unifying theory across taxa. We show that, in most cases, social competition drives the maintenance of female-limited polymorphism. Applying this framework to both within-sex and species-wide polymorphism reveals distinctions and commonalities across disparate taxa, provides a clear structure for developing hypotheses, and reveals new paths for future research in the adaptive maintenance of polymorphism. https://doi.org/10.32942/X2291Q Life Sciences polymorphism, balancing selection, social selection, adaptation, female-limited polymorphism Published: 2025-04-15 12:24 Last Updated: 2025-04-15 12:24 CC-By Attribution-NonCommercial-NoDerivatives 4.0 International Data and Code Availability Statement: Not applicable Language: English