Acoustic communication in territorial butterflyfish: test of the sound production hypothesis

Abstract

SUMMARY Butterflyfishes are conspicuous members of coral reefs and well known for their visual displays during social interactions. Members of the genus Chaetodon have a unique peripheral arrangement of the anterior swim bladder that connects with the lateral line (the laterophysic connection) and in many species projects towards the inner ear. This morphology has lead to the proposal that the laterophysic connection and swim bladder system may be a specialized structure for the detection of sound. However, the relevant stimuli, receiver mechanisms and functions for these putative hearing structures were unknown because butterflyfishes were previously not recognized to produce sounds during natural behavior. We performed field experiments to test the hypothesis that Chaetodon produces sounds in natural social contexts. Acoustic and motor behaviors of the monogamous multiband butterflyfish, C. multicinctus, were evoked and recorded by placement of bottled fish into feeding territories of conspecific pairs. We demonstrate that territory defense includes the production of agonistic sounds and hydrodynamic stimuli that are associated with tail slap, jump, pelvic fin flick and dorsal-anal fin erection behaviors. In addition, grunt pulse trains were produced by bottled intruders and are tentatively interpreted to function as an alert call among pair mates. Acoustic behaviors include low frequency hydrodynamic pulses <100 Hz, sounds with peak energy from 100 Hz to 500 Hz,and a broadband high frequency click (peak frequency=3.6 kHz), which is produced only during the tail slap behavior. These results provide a biological framework for future studies to interpret the proximate function of the acoustico-lateralis sensory system, the evolution of the laterophysic mechanism and their relevance to butterflyfish social behavior.

Vocalisations of the bigeye Pempheris adspersa: characteristics, source level and active space

“…Damselfishes (Pomacentridae) produce pulsatile sounds (one to 22 pulses) that have peak frequencies between 300 and 1000 Hz, pulse duration between 10 and 30 ms and pulse period between 8 and 120 ms (Amorim, 2006;Chen and Mok, 1988;Lobel and Kerr, 1999;Luh and Mok, 1986;Mann and Lobel, 1998;Myrberg et al, 1993;Parmentier et al, 2010Parmentier et al, , 2011. Squirrelfish (Holocentridae) and butterflyfish (Chaetodontidae) produce vocalisations with peak frequencies between 80 and 130 Hz (Parmentier et al, 2011) and 90 and 300 Hz (Boyle and Tricas, 2010;Tricas et al, 2006), respectively, with pulse duration in the range 30-60 ms. In terms of pulse number, pulse period and dominant frequency, the bigeye vocalisation characteristics were comparable to the lower range of the respective values for coral reef fishes.…”

“…In coral reef habitats, the diversity of fish species is matched by a diversity of soniferous species, especially members from the families Pomacentridae (Myrberg et al, 1993;Parmentier et al, 2009Parmentier et al, , 2006, Holocentridae (Parmentier et al, 2011) and Chaeotodontidae (Boyle and Tricas, 2010;Tricas et al, 2006). The types of vocalisations produced are almost as diverse as the number of species that produce sounds.…”

“…The types of vocalisations produced are almost as diverse as the number of species that produce sounds. These include a variety of chirps (Chen and Mok, 1988;Lobel and Kerr, 1999;Luh and Mok, 1986), grunts (Amorim, 2006;Tricas et al, 2006) and pops (Mann and Lobel, 1998;McCauley and Cato, 2000). Daily patterns of sound production are also evident, with highest activity levels during crepuscular periods that correspond to increased behavioural activities, such as mating and territorial defence (Parmentier et al, 2010).…”

Diversity and evolution of sound production in the social behavior ofChaetodonbutterflyfishes

“…Several Chaetodon subgenera show distinct differences in the length, width and proximity of the paired anterior swim bladder horns to a medial opening in the lateral line canals in the supracleithral bone of the head and in the morphology of the swim bladder (Webb and Smith, 2000;Webb et al, 2006Webb et al, , 2010. The LC system was proposed to enhance hearing capabilities during social interactions via the transduction of sound pressure waves by the anterior swim bladder horns that may stimulate fluid motion in the lateral line canal and particle motion at the inner ear (Webb, 1998;Webb et al, 2006;Tricas et al, 2006). However, the acoustic behaviors and sound characteristics used in communication by Chaetodon remain unknown for all but one species, and are needed to interpret the putative function and evolution of the LC within the family.…”

Sound production in the longnose butterflyfishes (genusForcipiger): cranial kinematics, muscle activity and honest signals

“…The pebbled butterflyfish (Chaetodon multicinctus) is a socially monogamous species, and produces several classes of sounds during agonistic interactions with conspecifics in defense of coral feeding territories and towards mates in a putative distress call context (Tricas et al, 2006). The direct mechanism for sound production by pebbled butterflyfish, however, remains unknown.…”