Habitat influence on the evolution of male mating vocalizations in subterranean and surface-dwelling rodents (Rodentia)

Abstract

The acoustic adaptation hypothesis (AAH) is often tested between species from open and closed habitats. However, the acoustic differences are rather small and thus the evidence is ambiguous. We tested the AAH between subterranean and surface-dwelling species living in very different acoustic environments. Lower frequencies (<1 kHz) are transmitted best in subterranean burrows and there is a high-frequency cut off around 3 kHz. The other important factor influencing the frequencies of vocal signals is body size. Acoustic allometry – a negative relationship between body size and frequency of acoustic signals – indicates that larger species tend to produce sounds of lower frequencies than smaller species, due to their larger vocal apparatus. The present study shows, that acoustic allometry applies to subterranean as well as surface-dwelling rodents and that the environment influences the main frequency of their vocalization. Besides, the subterranean species tend to have lower vocal signals than surface-dwelling species.