Acoustic communication in the electric yellow cichlid, Labiochromis caeruleus.

Abstract

The cichlidae represent an attractive model for acoustic communication as their well‐characterized adaptive radiation can serve as a backdrop for testing evolutionary hypotheses. Despite interest in sound communication in cichlids, little is known of their hearing ability and less is known about hearing and sound production in the same species. The current study examined sound production, hearing, and auditory morphology in a Lake Malawi cichlid Labidochromis caeruleus. Males and females were paired in the laboratory and all behavioral and acoustic displays recorded. Hearing was tested to tone bursts and samples of recorded calls using auditory evoked potentials and morphology was assayed using MicroCT scans of intact fish. Males produced calls with dominant frequency of approximately 300 Hz but only when simultaneously performing a quiver display. Fish detected tones from 100–1000 Hz and were more sensitive to tones than to playbacks of call segments. Finally, MicroCT showed a heart‐shaped swim bladder with anterior protrusions directed at the large saccular otoliths, possibly reducing self‐generated noise by focusing the call away from the ears. With this combination of behavioral, morphological, and physiological approaches, we were able to fully characterize acoustic communication in this species for the first time.