Abstract
Testosterone has recently been proposed as a link between male quality and health and the expression of sexual traits. We investigated the relationship between testosterone and measures of the individual condition and health of males in a natural population of house finches (Carpodacus mexicanus). We also conducted a captive experiment in order to test for the effects of testosterone on resistance to coccidia, which is a common parasite of house finches. Free-living males in better condition had higher testosterone levels and lower corticosterone levels than free-living males in poor condition. In our captive experiment, increased testosterone accelerated the rate of coccidial infection as compared with sham-implanted or gonadectomized males. Although the differences were not significant, free-living males infected with coccidia had lower levels of testosterone and higher levels of corticosterone than males that were not infected. Thus, experimentally elevating testosterone levels in captive males resulted in a higher percentage of infected males, while free-living males with coccidial infection had low testosterone levels. This apparent discrepancy between captive and free-living males in the association of testosterone and disease may be explained by the condition dependence of testosterone. These results suggest that the testosterone-dependent sexual traits reliably indicate male overall condition and health and, thus, females could benefit from assessing potential mates based on these traits.
Full Text
The Full Text of this article is available as a PDF (158.4 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chernin J., Morinan A. Analysis of six serum components from rats infected with tetrathyridia of Mesocestoides corti. Parasitology. 1985 Jun;90(Pt 3):441–447. doi: 10.1017/s0031182000055438. [DOI] [PubMed] [Google Scholar]
- Eens M., Van Duyse E., Berghman L., Pinxten R. Shield characteristics are testosterone-dependent in both male and female moorhens. Horm Behav. 2000 Mar;37(2):126–134. doi: 10.1006/hbeh.1999.1569. [DOI] [PubMed] [Google Scholar]
- Mendonça M. T., Chernetsky S. D., Nester K. E., Gardner G. L. Effects of gonadal sex steroids on sexual behavior in the big brown bat, Eptesicus fuscus, upon arousal from hibernation. Horm Behav. 1996 Jun;30(2):153–161. doi: 10.1006/hbeh.1996.0019. [DOI] [PubMed] [Google Scholar]
- Peters A. Testosterone treatment is immunosuppressive in superb fairy-wrens, yet free-living males with high testosterone are more immunocompetent. Proc Biol Sci. 2000 May 7;267(1446):883–889. doi: 10.1098/rspb.2000.1085. [DOI] [PMC free article] [PubMed] [Google Scholar]