Evol Ecol Res 5: 411-419 (2003)     Full PDF if your library subscribes.

Sexual ornamentation, androgens and papillomatosis in male roach (Rutilus rutilus)

Raine Kortet,* Anssi Vainikka, Markus J. Rantala, Ilmari Jokinen and Jouni Taskinen

Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, FIN-40351 Jyväskylä, Finland

Author to whom all correspondence should be addressed.
e-mail: rkortet@cc.jyu.fi

ABSTRACT

According to the immunocompetence handicap hypothesis, males with attractive sexual ornamentation are more handicapped than their less ornamented rivals because of the immunosuppressive androgens required for the production of secondary sexual characters. Here we studied the predictions of the hypothesis in a wild cyprinid fish, the roach (Rutilus rutilus). We assayed (1) sexual ornamentation (breeding tubercles), (2) circulating androgens (11-ketotestosterone and testosterone) and (3) epidermal papilloma disease of male roach at spawning. We found that elaborated sexual ornaments were associated with high circulating concentrations of testosterone and 11-ketotestosterone. Furthermore, papillomatosis was associated with high concentrations of testosterone and elaborated sexual ornaments. The results were consistent with the predictions of the immunocompetence handicap hypothesis. It had previously been shown in the present study system that breeding tubercles of males signal resistance against a predominant parasite, as predicted by the Hamilton and Zuk hypothesis. The present results suggest that male roach with high concentrations of circulating androgens express strongly secondary sexual characters, but may be at a high risk of papillomatosis. In the present system, we propose that papilloma disease, which occurs during spawning, may contribute to the honesty of the signal of sexual ornamentation in roach.

Keywords: immunocompetence, 11-ketotestosterone, ornaments, papillomatosis, sexual selection, testosterone.

DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.

 

        © 2003 Raine Kortet. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.