Population biology and fecundity of Leucothoe sp. (Crustacea, Amphipoda, Leucothoidae) associated to Phallusia nigra (Chordata, Tunicata) from the São Paulo Sebastião, northern of the State of São Paulo / Biologia populacional e fecundidade do anfipode endobionte Leucothoe sp. (Crustacea, Amphipoda, Leucothoidae) associado a Phallusia nigra (Chordata, Tunicata) do Canal de São Sebastião, litoral norte do estado de São Paulo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The aim of this study was to characterize the population biology and the fecundity of the gammaridean amphipod Leucothoe sp. associated to the ascidia Phallusia nigra on the Channel of São Sebastião, situated in the north coast of Estado de São Paulo, analyzing aspects such as population structure, growth, sex-ratio, fecundity, sexual dimorphism and mortality of this amphipod. Every two months, three ascidians had been collected in the sub littoral of eight rocky coasts of the Channel. The results were related with the temperature of the water and the biomass of the ascidian. Individuals of all development stages of Leucothoe sp. had been found associated with the P. nigra, characterizing this host as a steady and propitious environment for its reproduction and feeding. The association did not vary with the study period and wasn?t influenced by the biomass of the ascidians or by the water temperature. Most of the population of Leucothoe sp. inside P. nigra was composed by juveniles. The reduced number of adults can be related to the increase of mortality and to the exit of the juveniles for searching new hosts. The data related to the population, size structure and growth indicate that Leucothoe sp. can live from 7.2 to 11 months characterizing an semi-annual life cycle. The sex-ratio of Leucothoe sp. was deviated in favor of the females, fact probably related with migration and differential mortality of the males. The reproduction of Leucothoe sp. is continuous and the fecundity is positively related with body size, an usual pattern for gammarideans. Males and females of Leucothoe sp. present sexual dimorphism with morphologic differences in the second gnathopods

ASSUNTO(S)

razão sexual marine ecology population ecologia marinha população - biologia reprodução symbiosis simbiose sex-ratio reproduction

ACESSO AO ARTIGO

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