Plasma concentrations of sex steroids and fighting in male Tilapia zillii |
| |
Authors: | F C Neat I Mayer† † |
| |
Institution: | Fish Behaviour and Ecology Group, Division of Environmental and Evolutionary Biology, I.B.L.S. University of Glasgow, U.K.;Department of Zoology, University of Stockholm, S-106 91, Stockholm, Sweden |
| |
Abstract: | In laboratory-held Tilapia zillii the gonadosomatic index ( I G) is an accurate predictor of dominance in pairwise fights between males. Immediately after fighting no differences were detected between winners, losers or controls, in plasma concentrations of testosterone (T) or 11-ketotestosterone (11KT). 11KT was correlated negatively with I G and positively with T. 11KT appeared to be the major androgen in this species, but there was no evidence that simple differences in levels of these sex steroids mediated aggressive behaviour. |
| |
Keywords: | tilapia fighting testosterone 11-ketotestosterone gonadosomatic index |
|
|