Comportamento reprodutivo de Scinax albicans (Bokermann, 1967) (Anura, Hylidae), na Floresta Pluvial Montana no sudeste do Brasil

Abstract

Study of the reproductive biology of Scinax albicans, including aspects of life habits, territoriality, recruiting, survivorship, demographic parameters, male social organization, and environmental factors that affect the reproductive activity and vocalization, was performed in a section of a tributary to the Paquequer river, in the Municipality of Teresópolis, State of Rio de Janeiro, from September 2001 to September 2002. Fieldwork was done twice a month, totalizing 26 excursions and 72 days of field. Scinax albicans reproductive system is of the prolongued type. Reproductive activity occurred through the whole year, except for September 2002, as shown by the presence of the chorus or cluthes. The activity reproductive was strongly influenced by enviromentals factors such as rainfall, stream velocity and high temperatures. The avarege number of night in wich males remained in the chorus was 5.4 nights, representing 7.5% of the total number of nights sampled. The number of females was not significanthy correlated with the number of males and the operational sexual ratio (OSR) was negatively correlated with the number of males in the chorus. The number of eggs was positvely correlated with the size of the females. The average population size ofthe aggregation was 23.3 males. The mortality was low and recruiting was very variable through the year, with no clear sazonal pattern. The population size variation was better explained by mortality than recruiting. The observed mortality in the aggregation does not appear to be directly related to the resource availability of the population as whole and may reflect a high vulnerability of the males to predation, when they aggregate to reproduction.