Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.

Status signals allow competitors to assess each other's resource holding potential and reduce the occurrence of physical fights. Because status signals function to mediate competition over resources, a change in the strength of competition may affect the utility of a status signaling system. St...

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Main Authors: Philip S Queller, Troy G Murphy
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC5626437?pdf=render
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spelling doaj-679aaea906e748b7b066d19df6f3be4a2020-11-25T01:49:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-011210e018558410.1371/journal.pone.0185584Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.Philip S QuellerTroy G MurphyStatus signals allow competitors to assess each other's resource holding potential and reduce the occurrence of physical fights. Because status signals function to mediate competition over resources, a change in the strength of competition may affect the utility of a status signaling system. Status signals alter competitor behavior during periods of high competition, and thus determine access to resources; however, when competition is reduced, we expect these signals to become disassociated from access to resources. We investigated seasonal changes in status signaling of the male black-crested titmouse (Baeolophus atricristatus), a species that experiences substantial changes in population density and competition for food over the annual cycle. We compared the size of the prominent head-crest to foraging success at community-used feeding stations; we tested this relationship when competition was seasonally high, and when competition was seasonally low. We then experimentally decreased the number of feeders to increase competition (during the season of low-competition), and again tested whether male crest size predicted access to feeders. When competition was seasonally high, males with longer crests had greater access to feeders, but this pattern was not apparent when competition was seasonally low. When competition was experimentally increased, males with longer crests were again more successful at maintaining access to feeders. These findings provide evidence of a context-dependent status signaling system, where the status signal only mediates access to resources during periods of high competition. We discuss possible hypotheses for why the signaling system may not be functional, or detectable, during periods of low competition, including that competitors may interact less frequently and so have reduced opportunity for signaling, or that status signals are disregarded by receivers during periods of low competition because signalers are unlikely to escalate a contest into a fight. In any case, these results indicate that resource availability affects a status signaling system, and that the potential for status signaling persists in this system between seasons, even though such signaling may not be overtly present or detectable during periods of low competition.http://europepmc.org/articles/PMC5626437?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Philip S Queller
Troy G Murphy
spellingShingle Philip S Queller
Troy G Murphy
Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.
PLoS ONE
author_facet Philip S Queller
Troy G Murphy
author_sort Philip S Queller
title Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.
title_short Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.
title_full Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.
title_fullStr Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.
title_full_unstemmed Seasonal variation in the utility of a status signaling system: Plumage ornament predicts foraging success only during periods of high competition.
title_sort seasonal variation in the utility of a status signaling system: plumage ornament predicts foraging success only during periods of high competition.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2017-01-01
description Status signals allow competitors to assess each other's resource holding potential and reduce the occurrence of physical fights. Because status signals function to mediate competition over resources, a change in the strength of competition may affect the utility of a status signaling system. Status signals alter competitor behavior during periods of high competition, and thus determine access to resources; however, when competition is reduced, we expect these signals to become disassociated from access to resources. We investigated seasonal changes in status signaling of the male black-crested titmouse (Baeolophus atricristatus), a species that experiences substantial changes in population density and competition for food over the annual cycle. We compared the size of the prominent head-crest to foraging success at community-used feeding stations; we tested this relationship when competition was seasonally high, and when competition was seasonally low. We then experimentally decreased the number of feeders to increase competition (during the season of low-competition), and again tested whether male crest size predicted access to feeders. When competition was seasonally high, males with longer crests had greater access to feeders, but this pattern was not apparent when competition was seasonally low. When competition was experimentally increased, males with longer crests were again more successful at maintaining access to feeders. These findings provide evidence of a context-dependent status signaling system, where the status signal only mediates access to resources during periods of high competition. We discuss possible hypotheses for why the signaling system may not be functional, or detectable, during periods of low competition, including that competitors may interact less frequently and so have reduced opportunity for signaling, or that status signals are disregarded by receivers during periods of low competition because signalers are unlikely to escalate a contest into a fight. In any case, these results indicate that resource availability affects a status signaling system, and that the potential for status signaling persists in this system between seasons, even though such signaling may not be overtly present or detectable during periods of low competition.
url http://europepmc.org/articles/PMC5626437?pdf=render
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