The modulating effect of temperature on sexual differentiation and sex reversal in the freshwater crayfish Cherax quadricarinatus (Parastacidae).

VAZQUEZ, F.J.; TROPEA, C.; SÁNCHEZ DE BOCK, M.; LÓPEZ GRECO, L.S.

Coquimbo

Congreso; Mid-Year Meeting of the Crustacean Society; 2007

Temperature (T) is one of the most important modulating factors on reproduction in the freshwater crayfish C. quadricarinatus, "red claw". The influence of T on ovarian maturation and juvenile growth has been addressed. This work was aimed at studying the effect of temperature on sex differentiation and sex reversal as a possible factor for the culture of this species. Two kinds of experiments were carried out. In the first, recently hatched undifferentiated juveniles (20mg) were exposed at 27°C (control group), 29°C and 31°C and in the second experiment, juveniles females (200mg) were exposed at the same temperatures. Twice a week the animals were weighted and sexed. Both assays were run during 150 days. The results demonstrate that T is not a determinant factor on sexual differentiation but it has a significant (p<0.05) effect on sex reversal. The main type of sexual reversion is the change of sex from females toward intersex females although the reversion toward males was statistically significant (p<0.05) at 29°C. The assayed temperature of 29°C also induced greater somatic growth and early acquisition of sexual maturity in females so it is consider as an interesting factor to apply for the culture of the species.Financial support: UBACYT 2004-2007 (project X143), ANPCYT (PICT 2004-953), Antorchas Foundation (project 4248-138).