Physiological Basis of Convergent Evolution in Animal Communication Systems.

The article focuses on the convergent evolution of elaborate animal communication displays through the interaction of perceptual bias and ritualization, emphasizing mechanistic and physiological underpinnings. Perceptual bias refers to pre-existing sensory or cognitive preferences in receivers that shape signal evolution, often originating from systems used in feeding or predator avoidance, while ritualization describes the evolutionary co-option of non-communicative traits into intentional signals by signalers. Using foot-flagging frogs as a primary case study, the article illustrates how conserved neural feature analyzers (the "worm/antiworm" system) and androgen-sensitive muscle physiology facilitate the repeated independent evolution of this visual display in noisy environments where acoustic signals are less effective. Additional examples from fiddler crabs and lizards suggest that similar processes involving perceptual biases and ritualization contribute to convergent evolution of communication signals across diverse taxa. The authors propose further empirical tests to validate the roles of perceptual bias and ritualization in shaping these convergent displays.