title: Dissolved organic carbon and unimodal variation in sexual signal coloration in mosquitofish: a role for light limitation?
abstract: Natural selection plays an important role in the evolution of sexual communication systems. Here, we assess the effect of two well-known selection agents, transmission environment and predation, on interpopulation variation in sexual signals. Our model system is a series of 21 populations of Bahamian mosquitofish subjected to independent variation in optical conditions and predation risk. We show that optically diverse environments, caused by locally variable dissolved organic carbon concentrations, rather than spatial variation in predation, drove divergence in fin coloration (fin redness). We found a unimodal pattern of phenotypic variation along the optical gradient indicating a threshold-type response of visual signals to broad variation in optical conditions. We discuss evolutionary and ecological mechanisms that may drive such a pattern as well as the implications of non-monotonic clines for evolutionary differentiation.
authors.affiliation: Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA stgiery@gmail.com.
authors.forename: Sean T
authors.identifier: http://orcid.org/0000-0003-3774-5295
authors.initials: ST
authors.lastname: Giery
authors.affiliation: Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Layman
mesh_terms: D058500:Animal Fins / Q000502:physiology; D000818:Animals; D002244:Carbon / Q000737:chemistry*; D003532:Cyprinodontiformes / Q000235:genetics / Q000502:physiology*; D008027:Light; D010641:Phenotype; D010858:Pigmentation; D011235:Predatory Behavior; D012623:Seawater / Q000737:chemistry; D012641:Selection, Genetic
chemical_list: D002244:Carbon
keywords: Gambusia; Poeciliidae; communication; light limitation; natural selection; sexual selection