NEUMAN-LEE, Lori A.*; JANZEN, Fredric J.; Iowa State University, Ames; Iowa State University, Ames: Effects of Atrazine on Map Turtle (Graptemys) Development and Behavior

Atrazine is a widely used pre-emergent herbicide for controlling broadleaf plants. Since atrazine (a known endocrine disrupting chemical) is applied in the late spring and early summer, its incidental effects on species in aquatic areas containing run-off from terrestrial sources at this time are of special interest. To examine the possible secondary impact of atrazine, eggs were obtained from 10 nests of two closely related map turtles, Graptemys ouachitensis and G. pseudogeographica, which nest on water-saturated sandbars. Two eggs from each nest were incubated in sand containing one of four concentrations of atrazine (vehicle, 0.1ug/L, 10ug/L, 100ug/L) based on levels measured in the river adjacent to the site where eggs were collected. Hatching success, incubation length, external morphological abnormalities, three measures of body size, righting speed, and swimming speed were recorded for all turtles, and gonadal sex was assessed on a subset of the hatchlings. The remaining neonates were reared individually for 10 mo, during which time nest escape behavior, time to first foraging event, foraging speed, and growth were evaluated. Not one of the variables recorded at hatching was affected by atrazine treatment. However, turtles deriving from atrazine-treated eggs escaped much less frequently from their nest-like containers, started feeding > 2 wk later, and attacked live prey more slowly than turtles from control eggs. These findings reveal persistent fitness-reducing impacts of atrazine exposure during embryonic development on behavior of neonatal turtles.