Aggressiveness, reliable signaling and survival in a wild songbird

Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
Department of Psychology, University of Washington, Seattle, WA, USA
Department of Biology, University of Washington, Seattle, WA, USA
DOI
10.7287/peerj.preprints.1195v2
Subject Areas
Animal Behavior, Evolutionary Studies, Zoology
Keywords
honest signaling, territoriality, personality, aggression, survival, song sparrows
Copyright
© 2015 Akçay et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Akçay Ç, Campbell SE, Beecher MD. 2015. Aggressiveness, reliable signaling and survival in a wild songbird. PeerJ PrePrints 3:e1195v2

Abstract

The evolution and maintenance of honest or reliable signaling has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks in their territories to quantify their aggressiveness (flights, and close proximity) and aggressive signaling levels (rates of soft song, a close range signal reliably predicting attack) and asked whether these traits affect individuals’ survival on territory. We found that the effect of aggressive signaling via soft song interacted with aggressive behaviors such that there was a negative correlational selection: among males with low aggression, those males that signaled at higher levels (over-signalers) had higher survival whereas among males with high aggression those that signaled at low levels (under-signalers) survived longer. In other words, males who deviate from reliable signaling have a survival advantage. These results, along with previous research that suggested most of the deviation from reliable signaling in this system is in the form of under-signaling (high aggression males signaling at low levels) pose a puzzle for future research on how this reliable signaling system is maintained.

Author Comment

This is a revision in which the main analyses using Cox regression was replaced with Lande-Arnold phenotypic selection analyses as suggested by a reviewer. We also focus on a single signaling behavior, soft song in this version.