Investimento na função masculina em Biomphalaria tenagophila (ORBIGNY) (MOLLUSCA, PLANORBIDAE) avaliado pelo número de espermatozóides

Abstract

Investment in male function of Biomphalaria tenagophila (ORBIGNY) (MOLLUSCA, PLANORBIDAE) estimated by spermatozoa numbersBiomphalaria tenagophila is a simultaneous hermaphrodite whose male function investment was estimated by counting spermatozoa from ovotestis and seminal vesicle, under different experimental conditions during the copulation process. As a new technique, spermatozoa were separated in a detergent solution. In all experimental conditions the seminal vesicle contained at least twice as many spermatozoa as the ovotestis to the order of a hundred thousand in ovotestis compared with three or four hundred thousands in the seminal vesicle. There is evidence that the spermatozoa transferred in the copulation process originate from the donnor's seminal vesicle, and the balance of the number of spermatozoa in the seminal vesicle was restored in less than 24 hours.Key words: Biomphalaria tenagophila, mollusca, spermatozoa, numbers, couting. RESUMOBiomphalaria tenagophila é um hermafrodita simultâneo cujo investimento na função masculina foi avaliado pela contagem de espermatozóides do ovoteste e da vesícula seminal, sob diferentes condições experimentais, durante o processo de cópula. Foi criada uma nova técnica para contar espermatozóides separados em uma solução de alquilbenzeno sulfonato de sódio. Em todas as condições experimentais, a vesícula seminal teve mais do dobro de espermatozóides do ovoteste: da ordem de uma centena de milhar para três ou quatro centenas de milhares. Há evidências de que os espermatozóides transferidos no processo de cópula procederam da vesícula seminal do doador e que o equilíbrio do número de espermatozóides na vesícula seminal era restabelecido em menos de 24 horas.

The Influence of Self-fertilization performance and Copulation Behaviour in Reproduction by Cross-fertilization in Groups of Biomphalaria tenagophila (Mollusca, Planorbidae)

“…According to Rollinson et al (1989) it may be wrong to assume that all the snails in a population are equally well-balanced for tendencies to perform the female or male role. For Biomphalaria, is expected that female sexual role be more frequent, as long as they are included among the simultaneous hermaphrodite that practice "Gamete Commerce" (Monteiro & Dias 1989, Freitas 1994 , a general model of mating systems for simultaneous hermaphrodites that practice cross-fertilization, proposed by Leonard and Lukowiak (1984). The model consists of giving and receiving gametes in alternate and successive parcels.…”