Meeting Abstract

79.4  Tuesday, Jan. 6  Reduction of bubble nest frequency and size by male Betta splendens after exposure to 17Estradiol TODD, Nancy E.*; NEFF, Matt; Manhattanville College toddn@mville.edu

Betta splendens, known as the Siamese Fighting Fish, are notorious for their highly aggressive behavior toward each other. Males in particular have been selectively bred to enhance epigamic traits, such as bright colors and long, flowing fins. In addition to their aggression as an attractant for females, males build elaborate bubble nests to house fertilized eggs collected from the female. Many environmental estrogens are now present in aquatic ecosystems, resulting from pesticides, waste chemicals from factories, and other non-point sources. In the wild, these fish live in flooded rice paddies and other stagnant bodies of water in Asia, environments that are potentially susceptible to contamination by estrogenic compounds. The effects of these estrogens is beginning to emerge in studies of other species of fish that have reduced fertility, or undergo sex changes and transitions. In this study, male Betta splendens were exposed to 5ul of 17B estradiol for 28 days to evaluate the effect on their aggressive behavior and bubble nest construction. Behavior was examined pre-treatment, and 28 days after treatment, and the presence/absence of a bubble nest and its size was recorded. While the males were highly variable compared to each other and between behaviors, males that were exposed to 17B estradiol made significantly smaller bubble nests, or none at all, after treatment. More aggressive males made smaller bubble nests, while the less aggressive males made larger nests on average, but few made nests after exposure to 17B estradiol. These results highlight the potential effects of environmental estrogens on reproductive behavior in Betta splendens.