title: Shaping communicative colour signals over evolutionary time.
abstract: Many evolutionary forces can shape the evolution of communicative signals, and the long-term impact of each force may depend on relative timing and magnitude. We use a phylogenetic analysis to infer the history of blue belly patches ofSceloporuslizards, and a detailed spectrophotometric analysis of four species to explore the specific forces shaping evolutionary change. We find that the ancestor ofSceloporushad blue patches. We then focus on four species; the first evolutionary shift (captured by comparison ofS. merriamiandS. siniferus) represents an ancient loss of the belly patch byS. siniferus, and the second evolutionary shift, bounded byS. undulatusandS. virgatus, represents a more recent loss of blue belly patch byS. virgatus. Conspicuousness measurements suggest that the species with the recent loss (S. virgatus) is the least conspicuous. Results for two other species (S. siniferusandS. merriami) suggest that over longer periods of evolutionary time, new signal colours have arisen which minimize absolute contrast with the habitat while maximizing conspicuousness to a lizard receiver. Specifically, males of the species representing an ancient loss of blue patch (S. siniferus) are more conspicuous than are females in the UV, whereasS. merriamimales have evolved a green element that makes their belly patches highly sexually dimorphic but no more conspicuous than the white bellies ofS. merriamifemales. Thus, our results suggest that natural selection may act more immediately to reduce conspicuousness, whereas sexual selection may have a more complex impact on communicative signals through the introduction of new colours.
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA; Department of Biology, University of North Georgia, Oakwood, GA 30566, USA.
authors.forename: Alison G
authors.identifier: 0000-0002-6019-173X
authors.initials: AG
authors.lastname: Ossip-Drahos
authors.affiliation: Center for the Integrative Study of Animal Behavior , Indiana University , Bloomington, IN , USA.
authors.forename: José R
authors.initials: JR
authors.lastname: Oyola Morales
authors.affiliation: Departamento de Ciencias Veterinarias, Instituto de Ciencias Biomédicas , Universidad Autónoma de Ciudad Juárez , Ciudad Juárez , Mexico.
authors.forename: Cuauhcihuatl
authors.initials: C
authors.lastname: Vital-García
authors.affiliation: Departamento de Ecología y Recursos Naturales, Facultad de Ciencias , Universidad Nacional Autónoma de México , Mexico City , Mexico.
authors.forename: J Jaime
authors.identifier: 0000-0002-9661-1521
authors.initials: JJ
authors.lastname: Zúñiga-Vega
authors.affiliation: Department of Biology , Indiana State University , Terre Haute, IN , USA.
authors.forename: Diana K
authors.initials: DK
authors.lastname: Hews
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA.
authors.forename: Emília P
authors.initials: EP
authors.lastname: Martins
keywords: Sceloporus lizards; animal coloration; natural selection; sex differences; sexual selection; visual communication