Sound Production by a Coral Reef Fish (Pomacentrus Partitus): Evidence for a Vocal Territorial "Keep-out" Signal

Myrberg, Jr., Arthur

The Chirp-sound, produced by males of the bicolor damselfish Pomacentrus partitus, plays an important role in influencing the behavior of con specific females during the pre-spawning period. Evidence is provided here that the same sound possesses another function, i.e., it is a vocal, territorial "keep-out" signal. A field-study, conducted on a reef off southern Florida, showed that such sounds, when transmitted by an underwater loudspeaker from unguarded territories (residents removed), can inhibit territorial intrusion by neighboring male conspecifics for a significantly longer time than when such sounds are not transmitted from a territory. Evidence was also obtained that the visual presence of the resident was a more effective deterrent to intrusion, however, than sound-transmission. Finally, a significant relationship was found between the size of a given territory and the time of territory-intrusion by a neighboring conspecific male, suggesting that neighbors are aware of the resource holding potential of territorial residents. A brief laboratory study also indicated that the Chirp sounds of a resident were a more effective deterrent to territorial intrusion than Chirp-sounds of non-residents. Transmission of other sounds from unguarded territories, including random noise and feeding stridulations by residents and non-residents, showed no deterrent effect on territorial intrusion.

Sound Production by a Coral Reef Fish (Pomacentrus Partitus): Evidence for a Vocal Territorial "Keep-out" Signal

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