Sound production and spectral hearing sensitivity in the Hawaiian sergeant damselfish, Abudefduf abdominalis.

Sounds provide important signals for inter- and intraspecific communication in fishes, but few studies examine fish acoustic behavior in the context of coevolution of sound production and hearing ability within a species. This study characterizes the acoustic behavior in a reproductive population of the Hawaiian sergeant fish, Abudefduf abdominalis, and compares acoustic features to hearing ability, measured by the auditory evoked potential (AEP) technique. Sergeant fish produce sounds at close distances to the intended receiver (<or=1-2 body lengths), with different pulse characteristics that are associated primarily with aggression, nest preparation and courtship-female-visit behaviors. Energy peaks of all sounds were between 90 and 380 Hz, whereas courtship-visit sounds had a pulse repetition rate of 125 Hz with harmonic intervals up to 1 kHz. AEP threshold, which is probably higher than the behavioral threshold, indicates best sensitivity at low frequencies (95-240 Hz), with the lowest threshold at 125 Hz (123-127 dB(rms) re: 1 microPa). Thus, sound production and hearing in A. abdominalis are closely matched in the frequency domain and are useful for courtship and mating at close distances. Measured hearing thresholds did not differ among males and females during spawning or non-spawning periods, which indicates a lack of sex differences and seasonal variation in hearing capabilities. These data provide the first evidence that Abudefduf uses true acoustic communication on a level similar to that of both more derived (e.g. Dascyllus, Chromis) and more basal (e.g. Stegastes) soniferous pomacentrids. This correlation between sound production and hearing ability is consistent with the sensory drive model of signal evolution in which the sender and receiver systems coevolve within the constraints of the environment to maximize information transfer of acoustic signals.