Title
An experimental study on the causal relationships between (ecto-)parasites, testosterone and sexual signalling An experimental study on the causal relationships between (ecto-)parasites, testosterone and sexual signalling
Author
Faculty/Department
Faculty of Sciences. Biology
Publication type
article
Publication
Berlin ,
Subject
Psychology
Chemistry
Biology
Source (journal)
Behavioral ecology and sociobiology. - Berlin
Volume/pages
67(2013) :11 , p. 1791-1798
ISSN
0340-5443
ISI
000325765800007
Carrier
E
Target language
English (eng)
Full text (Publishers DOI)
Affiliation
University of Antwerp
Abstract
Bird song is considered to have evolved via sexual selection and should as such honestly signal aspects of the quality of its bearer. To ensure honesty, the immunocompetence handicap hypothesis proposed a dual role of testosterone, having positive effects on sexual signalling but suppressive effects on immune function. However, recent studies showed that it is rather an immune activation that suppresses the androgen production. This reversed chain of causation may significantly alter the pathways, which translate the effects of parasites and pathogens into changes in the expression of male sexual traits. We infested male canaries with Ixodes ricinus tick nymphs to investigate the causal relationships between (ecto-)parasites, testosterone and sexual signalling, here singing behaviour. We focused on flexible song traits, which may quickly reflect changes in the infestation status, and tested whether these effects relate to changes in the plasma testosterone levels or health state. The experimental tick infestation altered the males song performance by reducing song consistency, a trait that had previously been identified to reflect male quality. The tick infestation lowered the plasma testosterone levels and had a negative effect on the health status in terms of a reduced hematocrit. Our pathway analysis then revealed that it is the parasite-induced reduction of the plasma testosterone levels but not of the health state that caused the changes in song consistency. Thus, our study supports the view that it is the effect of parasites and immune activation on plasma testosterone levels that generates the trade-off between immunocompetence and sexual signalling.
E-info
https://repository.uantwerpen.be/docman/iruaauth/0291f2/4005752.pdf
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000325765800007&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000325765800007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000325765800007&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848
Handle