In ovum exposure to pesticides increases the egg weight loss and decreases hatchlings weight of Caiman latirostris (Crocodylia: Alligatoridae)

Abstract

The increasing use of pesticides affects ecosystem health. Caiman latirostris is a South American species with ecological and physiological features that render it vulnerable to exposure to pesticides with endocrine disruptor's action. Our main objective was to test the effect of in ovum exposure to atrazine and endosulfan on the sex ratio of caiman hatchlings; however, we are also presenting unexpected findings regarding pesticide effects on egg weight loss during incubation and hatchlings relative weight. Caiman eggs were incubated under controlled temperature (30 and 33 degrees C) and humidity (>90%). They were treated with vehicle, 17 beta-estradiol (1.4ppm), atrazine (0.2ppm) and endosulfan (0.02; 2; 20ppm). Pesticides did not cause estrogen-like effects on sex determination. Greater egg weight loss was observed in eggs treated with atrazine and higher doses of endosulfan (2 and 20ppm) (p=0.0005). These pesticides also caused a reduction in hatchling fractional weight (p=0.0497). These effects might have a significant impact on caiman population dynamics.