Effect of temperature on sex ratios of normal and gynogenetic diploid leach

Sex ratio was 1:1 in normal diploid leach Misgurnus anguillicaudatus reared at a temperature of 20 degrees C, but significant deviation of the ratio to the male was found when reared 25 and 30 degrees C for 214 days from day 6 after hatching. In gynogenetic diploids which were considered genetic females, no males were observed at 20 degrees C. In contast, gynogenetic males and intersexes were observed in groups reared at high temperatures (25 and 30 degrees C) for 220 or 240 days from day 11 after hatching. Incubation of gynogens at 28 degrees C for one month from day 11 after hatching was sufficient to produce males in gynogenetic diploids. These results indicated that high water temperature influences the sex of genetic females in the leach and then induces sex reversal to physiological males.