Meeting Abstract

53.1  Thursday, Jan. 5  Latent effects of embryonic exposure to atrazine on mating behaviors in guppies SHENOY, K.*; TOYODA, J.H.; Uinv. of Kentucky; Univ. of Kentucky

Endocrine disrupting compounds are ubiquitous in our environment, and impair hormonal functioning in exposed animals. Disruption of hormonally regulated traits, such as sexual behaviors, can potentially affect reproduction. Atrazine, a common herbicide, induces estrogen production in exposed animals. Often, pesticides are applied at specific times of year; environmental concentrations may peak for short periods at these times. This may span crucial developmental periods for many organisms, but the effects of exposure may be manifest at later life stages. We tested the latent effects of embryonic exposure to environmentally relevant doses of atrazine on mating behaviors in guppies (Poecilia reticulata), a viviparous tropical fish. Males are brightly colored and court females with characteristic displays. Females prefer males with more orange spots and that display more frequently. Adult female guppies were mated and exposed to treatments throughout the gestation period—control (no treatment), solvent control (DMSO), low dose (1 ppb) and high dose (10 ppb) of atrazine. Offspring born to these females were raised to adulthood without further treatment. Males and females were separated when discernable. At adulthood, males and females were tested for reproductive behaviors in separate trials—for males: frequency of courtship displays to females, and for females: preference strength for bright versus dull males. Atrazine exposed males were significantly less likely to perform courtship displays. But the number of displays was not different across treatments. There was a non-significant trend for atrazine exposed females to have a lower preference index. The results suggest that low sub-lethal doses of contaminants appearing briefly in the environment can have important implications to reproduction.