Bioecologia do caranguejo Armases rubripes (Rathbun, 1897) (Crustacea, Brachyura, Sesarmidae) na Ba?a de Sepetiba, RJ

• Ano de defesa: 2007
• Autor(a) principal: Lima, Giovana Valverde
• Orientador(a): Oshiro, Lidia Miyako Yoshii
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Biologia Animal
• Departamento: Instituto de Ci?ncias Biol?gicas e da Sa?de
• País: Brasil
• Palavras-chave em Português: Armases rubripes; Ba?a de Sepetiba; habitat; metapopula??o; libera??o larval; reprodu??o
• Palavras-chave em Inglês: Sepetiba Bay; habitats; metapopulation; reproduction; hatched
• Área do conhecimento CNPq: Ecologia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/tede/221

Armases rubripes is a crab abundant in northern South America. This work aimed to verify bioecological aspects of the crab Armases rubripes (Rathbun) in Sepetiba Bay/RJ, comparing its distribution, reproductive aspects and populational structure in three environments. The crabs were caught by hand on the beach and in the mangrove, while in the river they were obtained using sieves. The collections were carried out from July 2002 to January 2004. The animals were transported to the laboratory, where they were identified, sexed and measured. After, for the purpose of observing the larval liberation and analyzing the gonads microscopically anothers crabs were captured. A total of 4,051 crabs were caught in the three environments. The largest specimens were caught on the beach, while the smallest were obtained in the river. The populations presented five stages of sexual maturation. Recruitment, growth and frequency of older individuals are different in the above environments. A. rubripes did not present a definite period as regards the process of molt or the occurrence of terminal molt. Both physiological and morphological sexual maturity are presented asynchronically between the different populations, with the males maturing before the females. The microscopy carried out on the ovarian tissue corroborated the information obtained macroscopically. On the other hand, it was observed a presence of different spermatogenic lineage cells in the same seminiferous tubule indicates continuous activity. On the beach, A. rubripes presented continuous reproduction and average fecundity by 4,458 ? 2,739 eggs, while the mangrove had, in addition to seasonal-continuous reproduction and lower fecundity (2,005 ? 1,400 eggs). In the mangrove, the eggs that were analyzed (0.36 ? 0.11 mm) were larger than those obtained from the beach environment (0.25 ? 0.03 mm). The egg mass volume carried by the ovigerous females was also greater in the mangrove. The average fertility observed for the beach was 2,274 ? 1,017 larvae, while in the mangrove this average was 1,347 ? 580 larvae. This crab was presented a reduced loss of eggs during the incubation period. Armases rubripes hatched at night (03:00 to 04:00) during ebb tide. In relation to the composition of the diet of A. rubripes in the different environments of Sepetiba Bay, there was uniformity in the composition of the food resources consumed in the entire study period. The means food items were found: grasses and microalgae, with the most frequent items being Spartina alterniflora. Based on these results, this study verified that A. rubripes presents great plasticity in relation to the environments in which it is distributed. This brachyuran is successful in environments that it colonizes using strategies like production of larger-sized eggs, high fecundity and fertility with a reduced percentage of egg loss during embryonic development, continuous or seasonal-continuous reproduction, use of ebb tide for larval dispersion, size of distinct, asynchronic sexual maturity, continuous production of spermatozoids, absence of terminal molt with the continuous process of growth in the individuals of the populations and the use of differential spatial distribution between immature and mature individuals.