(A) Gain (top), phase (middle) and offset (bottom) as a function of carrier frequency for a given envelope frequency of 0.001 Hz for all three species tested (A. leptorhynchus, black; A. albifrons, red; Sternopygus sp., blue). (B) Gain (top), phase (middle) and offset (bottom) as a function of carrier frequency for a given envelope frequency of 0.0025 Hz for all three species tested (colors as in A). Open circles indicate statistically significant difference with values obtained for A. leptorhynchus at the P=0.05 level using an ANOVA with Bonferroni correction. Errors bars show s.e.m.