The choice of bromeliads as a microhabitat by Scinax argyreornatus (Anura, Hylidae).

The association of anurans to bromeliads presents different degrees of interaction such as: eventual, obligatory and bromeligen. The frog species Scinax argyreornatus shows a regular association with these plants. The goal of this study is to characterise the degree of association between the frog S. argyreornatus to different species of bromeliads. We identified which species of bromeliad is regularly associated with S. argyreornatus and recognised which factors interfere with this association preference. We analysed the Concentration of Relative Dominance of frogs per bromeliad species. As possible criteria for frog association preference to different bromeliads species we established the analysis of leaves number, length and width, number of leaf axils, stored water in the axils, pH and relative humidity, among other organographic components. Our observations were analyzed by ANOVA followed by the Tukey test. We also evaluated the preference for association by the constancy of Bodenheimer. The correlation matrix indicated that the relative humidity is the factor responsible for the frog-bromeliads association, except for Aechmea sp.. However Aechmea sp. was the species with greater constancy of occupation followed by Quesnelia arvensis and Neoregelia johannis. According to our statistical results, Aechmea sp. and Q. arvensis are not different regarding organographic parameters, but differ from N. johannis. Our observations suggest that the bromeliads organographic structure and the relative humidity are key conditions which influence the preferences of S. argyreornatus to bromeliad species, while the other features showed no correlation.