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UBC Theses and Dissertations

Effects of gonadectomy and methyl testosterone on the reproductive behavior of the blue gourami (Trichogaster trichopterus) Johns, Laurence Sipprell


The blue gourami (Trichogaster trichopterus), does not appear to go through a ritualized prespawning behavior sequence. The female is apparently brought into a state of sexual activity as a result of the presence of a dark, nest building male. Spawning is initiated by the female and it consists of a stereotyped cycle of behavioral events. In the majority of cases, male castration results in the cessation of nest building, a reduction of colour change, a partial atrophy of the morphological secondary sexual characteristics (S.S.C.), and the absence of spawning. Treatment with methyl testosterone brings back all of these characteristics. In a few cases, castration resulted in only a partial reduction of nest-building, colour change and morphological secondary sexual characteristics and the retention of spawning. It is tentatively suggested that there may be an extragonadal source of androgen. It seems the physical act of spawning is necessary to trigger full parental behavior regardless of gonadal condition. Agonistic behavior is not apparently affected by castration. Methyl testosterone given to unoperated females resulted in male-like agonistic behavior, coloration, secondary sexual characteristics and some evidence of nest building.

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