How do tree density and body size influence acoustic signals in Amazonian nurse frogs?

The Acoustic Adaptation Hypothesis (AAH) predicts that acoustic signals emitted at sites with greater vegetation density should have spectral and temporal characteristics increase signal transmission, but there is a pleiotropism related to body size: large animals produce lower frequency. We used 238 advertisement calls of 34 populations Amazonian nurse frogs from two rainforests different test if tree influences the evolution parameters. PGLS for relationships between traits phenotypic, environmental geographic predictors. Spectral features an allometric relationship size. found novel quadratic note duration dominant frequency size direct effect indicates evolutionary trajectories follow general macro-evolutionary pattern as in birds. opposite those predicted by AAH; environments emit longer notes higher rates than denser-tree environments. Subtle differences forest types can drive diversification micro-evolutionary scales.