Biologia e Ecologia Populacional de Ctenus Fasciatus Mello-Leitão e Enoploctenus Cyclothorax (Bertkau) em Cavernas do Alto Ribeira, Iporanga, SP (Araneae: Ctenidae)


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January 2004


Ctenus fasciatus e Enoploctenus cyclothorax (Araneae: Ctenidae) from caves in the Alto Ribeira karst area, Iporanga Co., southern State of São Paulo, were studied with focus on their distribution in the subterranean habitat, population ecology, movements, feeding, and reproduction and growth. The populations of C. fasciatus from Lage Branca Cave, in the Parque Estadual Turístico do Alto Ribeira (PETAR), and from four caves in the Parque Estadual Intervales (Barra Bonita, do Tatu, do Fóssil Desconhecido e Toca Detrás), as well as those of E. cyclothorax found in the latter, were investigated using mark-recapture techniques. These populations are seasonal, with a peak in the number of observed specimens coincident with the reproductive season, which occurs in the summer (November to March) for C. fasciatus and in the winter for E. cyclothorax. There was an accentuated decrease in the population of C. fasciatus in the Lage Branca Cave from the first to the second study year (2001 to 2002), possibly due to floodings and/or poorly controlled touristic visitation. A less accentuated population decrease was also observed for C. fasciatus in caves from the PEI, possibly representing a natural fluctuation. For E. cyclothorax, the study in the PEI indicates that the males are errant and the females tend to be sedentary, and that the adult population renews every year. Females of E. cyclothorax are non-obligatory trogloxenes (aparently males do not use the hypogean habitat), whereas C. fasciatus is a typical troglophile rarely found in the epigean environment. The latter is found throughout the caves, in different substrata (walking on the floor, on rocky walls, hidden in crevices or log); 140 m long movements within 4-5 months were observed for two individuals. Individuals of both species, as well as Isoctenus sp. from a cave in São Domingos karst area, State of Goiás, Central Brazil, were kept in laboratory for study of reproduction and postembryonic development. Development in C. fasciatus and Isoctenus sp. Takes a long


Behavior, Biology, Cave Spiders, Ctenidae, Ecology, Wandering Spiders

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