Carotenoids, sexual signals and immune function in barn swallows from Chernobyl

Citation
A. Camplani et al., Carotenoids, sexual signals and immune function in barn swallows from Chernobyl, P ROY SOC B, 266(1424), 1999, pp. 1111-1116
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Experimental Biology
Journal title
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES
ISSN journal
0962-8452 → ACNP
Volume
266
Issue
1424
Year of publication
1999
Pages
1111 - 1116
Database
ISI
SICI code
0962-8452(19990607)266:1424<1111:CSSAIF>2.0.ZU;2-#
Abstract
Carotenoids have been hypothesized to facilitate immune function and act as free-radical scavengers, thereby minimizing the frequency of mutations. Po pulations of animals exposed to higher levels of free radicals are thus exp ected to demonstrate reduced sexual coloration if use of carotenoids for fr ee-radical scavenging is traded against use for sexual signals. The intensi ty of carotenoid-based sexual coloration was compared among three populatio ns of barn swallows Hirundo rustica differing in exposure to radioactive co ntamination. Lymphocyte and immunoglobulin concentrations were depressed, w hereas the heterophil:lymphocyte ratio, an index of stress, was enhanced in Chernobyl swallows compared to controls. Spleen size was reduced in Cherno byl compared to that of two control populations. Sexual coloration varied s ignificantly among populations, with the size of a secondary sexual charact er (the length of the outermost tail feathers) being positively related to coloration in the two control populations, but not in the Chernobyl populat ion. Thus the positive covariation between coloration and sexual signalling disappeared in the population subject to intense radioactive contamination . These findings suggest that the reliable signalling function of secondary sexual characters breaks down under extreme environmental conditions, no l onger providing reliable information about the health status of males.