Sex Reversal in Honmoroko, Gnathopogon caurulescens by Immersion in 17-Methyltestosterone and an Attempt to Produce All-Female Progeny

Abstract

Functional sex reversal from female to male in honmoroko, Gnathopogon caurulescens was carried out by immersion in 17-methyltestosterone (17-MT) and examined whether it was possible to produce all-female progeny by using sex-inverted males. When 17-MT was administered to gynogenetic diploids at 0.1μg/l water (for 17 h per day) for 30 days from 15 days after hatching, proportion of matured males significantly increased. Futhermore, 17-MT at 0.1μg/l water (throughout the day) treated for 50 days from 10 days after hatching could performed more complate masculinization. light water temperature (28°C) during hormone treatment accelerated the sex reversal. Three thousand offspring produced by possible sex-inverted males mated with normal females contained 73 % females which was 34% higher than that of the control and showed same growth of the control. These results suggested that honmoroko is basically female homogamety, despite of including partially males.