EMBRYONIC EXPOSURE TO LOW-DOSE PESTICIDES: EFFECTS ON GROWTH RATE IN THE HATCHLING RED-EARED SLIDER TURTLE

Abstract

In the red-eared slider turtle, pesticides can alter expected sex outcomes, a major step in the inferred pathway of sex determination, and hatchling steroid physiology. Changes such as these can profoundly affect an organism's fitness. Other potential markers for effects on fitness include hatchling mass, hatchling use of maternal stores (residual yolk), and especially early hatchling growth rates. In the current study, red-eared slider turtles were exposed during embryogenesis to one of three compounds--chlordane, trans -Nonachlor, or p,p'-DDE--all of which affect sex determination in this species. Turtles were weighed at hatching, after a 28-d fasting period, and after 14 d of ad libitum feeding. All three compounds had some population-wide effects on changes in mass from time point to time point when compared to controls. From hatching to the end of the 28-d fast, turtles exposed in the egg to the mid-range doses of trans -Nonachlor and of p,p'-DDE lost mass and underwent a change in mass significantly different from controls. Additionally, turtles exposed to the two higher doses of trans -Nonachlor and the mid-range dose of chlordane grew significantly more than controls after 14 d of ad libitum feeding. These results point to a role for pesticides in endocrine disruption that extends beyond sex determination and sex development.