Advanced

Epaulet size and current condition in red-winged blackbirds : Examining a semistatic signal, Testosterone, Immune function, And parasites

Merrill, Loren; Stewart, Tara E.; González-Gómez, Paulina L.; O’Loghlen, Adrian L.O.; Wingfield, John C; Ellis, Vincenzo A. LU and Rothstein, Stephen I. (2015) In Physiological and Biochemical Zoology 88(1). p.11-21
Abstract

Some sexually selected signals are thought to convey information about the current condition and genetic/epigenetic quality of the individual signaling, including the ability to resist parasites. However, it is unclear whether semistatic sexual signals that develop periodically and remain stable over protracted periods, such as avian breeding plumage, can relate to measures of current condition and health. We examined a semistatic signal (wing epaulet size) in male redwinged blackbirds (Agelaius phoeniceus) during the breeding season and looked for relationships between this trait and circulating testosterone (T), hematocrit, bacteriakilling ability (BKA) of the blood, and the infection status, richness, and abundance of four functional... (More)

Some sexually selected signals are thought to convey information about the current condition and genetic/epigenetic quality of the individual signaling, including the ability to resist parasites. However, it is unclear whether semistatic sexual signals that develop periodically and remain stable over protracted periods, such as avian breeding plumage, can relate to measures of current condition and health. We examined a semistatic signal (wing epaulet size) in male redwinged blackbirds (Agelaius phoeniceus) during the breeding season and looked for relationships between this trait and circulating testosterone (T), hematocrit, bacteriakilling ability (BKA) of the blood, and the infection status, richness, and abundance of four functional categories of parasite. We found that epaulet size was positively related to circulating levels of T and ectoparasite infections. We found no relationships between T and parasite infections. In adult males there was a negative relationship between T and BKA, whereas in yearling males there was no relationship. We found no evidence for a general reduction in immunocompetence in males with larger epaulets but rather an increase in susceptibility to specific types of parasites. Our results suggest that semistatic signals can be linked to measures of current condition, and we postulate that these relationships are modulated via activity levels related to breedingseason activities.

(Less)
Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
subject
in
Physiological and Biochemical Zoology
volume
88
issue
1
pages
11 pages
publisher
University of Chicago Press
external identifiers
  • scopus:84920675964
ISSN
1522-2152
DOI
10.1086/679475
language
English
LU publication?
no
id
7cce3569-8625-44fc-a57c-5feb55f5e1fe
date added to LUP
2017-05-09 17:14:03
date last changed
2017-10-01 05:34:09
@article{7cce3569-8625-44fc-a57c-5feb55f5e1fe,
  abstract     = {<p>Some sexually selected signals are thought to convey information about the current condition and genetic/epigenetic quality of the individual signaling, including the ability to resist parasites. However, it is unclear whether semistatic sexual signals that develop periodically and remain stable over protracted periods, such as avian breeding plumage, can relate to measures of current condition and health. We examined a semistatic signal (wing epaulet size) in male redwinged blackbirds (Agelaius phoeniceus) during the breeding season and looked for relationships between this trait and circulating testosterone (T), hematocrit, bacteriakilling ability (BKA) of the blood, and the infection status, richness, and abundance of four functional categories of parasite. We found that epaulet size was positively related to circulating levels of T and ectoparasite infections. We found no relationships between T and parasite infections. In adult males there was a negative relationship between T and BKA, whereas in yearling males there was no relationship. We found no evidence for a general reduction in immunocompetence in males with larger epaulets but rather an increase in susceptibility to specific types of parasites. Our results suggest that semistatic signals can be linked to measures of current condition, and we postulate that these relationships are modulated via activity levels related to breedingseason activities.</p>},
  author       = {Merrill, Loren and Stewart, Tara E. and González-Gómez, Paulina L. and O’Loghlen, Adrian L.O. and Wingfield, John C and Ellis, Vincenzo A. and Rothstein, Stephen I.},
  issn         = {1522-2152},
  language     = {eng},
  number       = {1},
  pages        = {11--21},
  publisher    = {University of Chicago Press},
  series       = {Physiological and Biochemical Zoology},
  title        = {Epaulet size and current condition in red-winged blackbirds : Examining a semistatic signal, Testosterone, Immune function, And parasites},
  url          = {http://dx.doi.org/10.1086/679475},
  volume       = {88},
  year         = {2015},
}