Meeting Abstract

P2.33  Thursday, Jan. 5  Dyadic Interactions in the mixed-mating strategies of the mangrove rivulus, Kryptolebias marmoratus. I. The role of hermaphrodite-male and hermaphrodite-hermaphrodite dyads. LUKE, Kelly/N.*; BECHLER, David/L.; South Georgia College, Douglas, GA; Valdosta State University, Valdosta, GA

The mangrove rivulus, Kryptolebias marmoratus, is a small cyprinodont fish native to tropical and subtropical waters of Florida, Brazil, and the Caribbean. It is the only known self-fertilizing, hermaphroditic vertebrate and the only one to display androdioecy, a complex reproductive system involving hermaphrodites and males most often seen in plants and some invertebrates. Kryptolebias marmoratus dyads exhibited a total of 23 distinctive behaviors. Acts were divided into four categories: aggressive, submissive, neutral, and reproductive. Leading and following behaviors played important roles in the behavioral repertoires of these fish. In the hermaphrodite-male dyad, males initiated the reproductive process exclusively and actively pursued the hermaphrodite. Hermaphrodites were especially receptive to male tactile acts and responded with a unique set of behaviors not seen in the hermaphrodite-hermaphrodite dyad. No spawning acts were observed nor were eggs recovered from the observation tank suggesting that actual spawning may be rare or that courtship is protracted. Hermaphrodite-hermaphrodite dyads showed no evidence that they behaved like other simultaneous hermaphrodites alternating sex roles nor were any reproductive behaviors observed. Rather, dyads were extremely aggressive towards one another with the aggressor establishing dominance immediately. Most lead acts involved aggression by the dominant fish followed by submissive acts from the subordinate. These findings support the hypothesis that heterozygosity observed in wild populations resulted from hermaphrodite-male outcrossing and not hermaphrodite-hermaphrodite outcrossing.