Body size and wing shape as predictors of the initial flight acceleration in bats of the Brazilian Atlantic Forest

Bat body size and some aspects of the wing shape are considered efficient indicators of bat flight performance. Here, we evaluated how body size and wing shape can be predictors of initial flight acceleration (0-10 meters) in 15 bat species (3 families) occurring in the Atlantic Forest. Two body size variables (wingspan and body mass) and three wing shape variables (relative wing loading, aspect ratio and wing tip index) were taken from 74 individuals. We carried out flight experiments with another 59 individuals, to evaluate the Initial Flight Acceleration (IFA). We used generalized linear models (GLM) to evaluate which variables were the best predictors of initial flight acceleration. Furthermore, we tested the phylogenetic signal for initial flight acceleration, and the hypothesis of phylogenetic autocorrelation for this behavior was discarded (p > 0.05). Our results show that larger species with narrow wings need to develop greatest initial accelerations to take off flight. We suggest a morphological restriction on flight, since most bat species analyzed have low values in both variables and those that have high values are only in one of these variables.