The Role of Dyadic Interactions in the Mixed-mating Strategies of the Mangrove Rivulus, Kryptolebias marmoratus.
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Authors
Luke, Kelly Nicole
Issue Date
2011-08-26
Type
Thesis
Language
en_US
Keywords
Kryptolebias marmoratus , dyadic interactions , androdioecy , hermaphrodite , mangrove rivulus.
Alternative Title
Abstract
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 vertebrate to display
androdioecy, a complex system of reproduction in which hermaphrodites and males are
present. This study describes the behavioral repertoires observed during dyadic
interactions staged in the laboratory. Kryptolebias marmoratus exhibited a total of 23
distinctive acts or 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. When two hermaphrodites were paired together, there was no evidence that hermaphrodites behave like other simultaneous hermaphrodites and alternate sexual roles. Hermaphrodites were extremely aggressive towards one another and the aggressor established dominance rapidly. Male-male dyads were divided into two subdivisions based on the presence or absence of the caudal ocellus. It appeared the presence of the caudal ocellus signaled to males the possibility of a potential mating partner. When no ocellus was present in either male, their behavior was similar to hermaphroditehermaphrodite dyads, in that both members of the pair were aggressive towards one another. These observations may be indicative of interactions taking place in natural communities or assemblages of fish where both males and hermaphrodites occur, and provide evidence on the role of dyadic interactions in the mixed-mating strategies of the mangrove rivulus.