EFEITO DA TEMPERATURA E PRECIPITAÇÃO NA DETERMINAÇÃO SEXUAL DE Caiman latirostris

SIMONCINI, M.; PIÑA, C.I.; CRUZ F.B.; LARRIERA, A.; RICE, K.G.

Manaos

Congreso; 20th Working Meeting of the Crocodile Specialista Group (CSG/SSC/IUCN); 2010

CSG/SSC/UICN

Caiman latirostris shows temperature-dependent sex determination (TSD) in laboratory, Under natural conditions, several factors influence nest temperature, probably affecting the proportion of females to be born. We studied 83 wild nests within a period of 8 years (from 2000 to 2009, except for 2003). We related the proportion of hatched females with climate variables from a database field. All the studied nests were harvested in the wild after the thermo sensitive period and hatchlings were sexed at about one year of age (1320 caimans). In addition, we installed data loggers’ thermometers in 20 nests with the aim of evaluating the effect of environmental conditions on nests temperature and the proportion of born females. We found differences in the percentage of females born between seasons (from 47% to 89%) but it was not related to any of the climatic variables analyzed. Regarding the nests with data loggers, we observed that when the average nest temperature rises during the thermo sensitive period, the percentage of females born decreased. However, this proportion was only related to the temperature inside the nest and not to outer environmetal temperature.