title: Phylogenetic analysis of the evolution of a signal of aggressive intent in northern swordtail fishes.
abstract: The initiation of a coevolutionary relationship between signal and response can be explained by either the receiver taking advantage of information inadvertently provided by the sender or the sender taking advantage of a perceptual bias in the receiver. In addition, once both signal and response are present, the exchange of information may or may not be cooperative. We examined the evolution of a signal of aggressive intent (expression of vertical bars) across all the northern swordtail fishes (Xiphophorus) in a phylogenetic context. We found that the signal was present before responses evolved, which suggests that this coevolutionary relationship was initiated by the receiver taking advantage of information inadvertently provided by the signaler. In addition, we introduce a novel method for examining the cooperative nature of signaling systems and provide some evidence to suggest that in this signaling system, receivers may be exploiting an honest signal in some species.
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405, USA. jmoretz@indiana.edu
authors.forename: Jason A
authors.initials: JA
authors.lastname: Moretz
authors.forename: Molly R
authors.initials: MR
authors.lastname: Morris
mesh_terms: D000374:Aggression / Q000502:physiology*; D000819:Animal Communication; D000818:Animals; D003532:Cyprinodontiformes / Q000235:genetics* / Q000502:physiology*; D005260:Female; D008297:Male; D010802:Phylogeny