Overview on the Diversity of Sounds Produced by Clownfishes (Pomacentridae): Importance of Acoustic Signals in Their Peculiar Way of Life

Abstract

BackgroundClownfishes (Pomacentridae) are brightly colored coral reef fishes well known for their mutualistic symbiosis with tropical sea anemones. These fishes live in social groups in which there is a size-based dominance hierarchy. In this structure where sex is socially controlled, agonistic interactions are numerous and serve to maintain size differences between individuals adjacent in rank. Clownfishes are also prolific callers whose sounds seem to play an important role in the social hierarchy. Here, we aim to review and to synthesize the diversity of sounds produced by clownfishes in order to emphasize the importance of acoustic signals in their way of life.Methodology/Principal FindingsRecording the different acoustic behaviors indicated that sounds are divided into two main categories: aggressive sounds produced in conjunction with threat postures (charge and chase), and submissive sounds always emitted when fish exhibited head shaking movements (i.e. a submissive posture). Both types of sounds showed size-related intraspecific variation in dominant frequency and pulse duration: smaller individuals produce higher frequency and shorter duration pulses than larger ones, and inversely. Consequently, these sonic features might be useful cues for individual recognition within the group. This observation is of significant importance due to the size-based hierarchy in clownfish group. On the other hand, no acoustic signal was associated with the different reproductive activities.Conclusions/SignificanceUnlike other pomacentrids, sounds are not produced for mate attraction in clownfishes but to reach and to defend the competition for breeding status, which explains why constraints are not important enough for promoting call diversification in this group.

The cerato-mandibular ligament: a key functional trait for grazing in damselfishes (Pomacentridae)

“…Sounds in pomacentrids are produced by a jaw slam that causes teeth collision [32,35,47]; for this reason the start of the sound corresponds to the bite. The sounds produced during fighting and during the biting of filamentous algae can be clearly recorded with a hydrophone.…”

“…The farming behavior involves the defense of a patch of territory from which roving grazers, such as acanthurids, scarids or siganids, are chased; cleaning up of debris; and weeding out undesirable algae [29,30]. Sounds from damselfishes are well-known and occur during aggressive territory defense and/or courtships [31][32][33][34]. In the zooplanktivorous Amphiprion clarkii, aggressive sounds result from teeth collision induced by a buccal jaw slam [35].…”

Acoustic signalling in female fish: factors influencing sound characteristics in croaking gouramis

“…Examples include croaking gouramis (male T. vittata, T. schalleri, T. pumila -Ladich et al 1992), damselfish (male Stegastes partitus -Myrberg et al 1993; Amphiprion spp. -Colleye et al 2009;Colleye and Parmentier 2012), catfishes (Corydoras paleatus both sexes pooled - Pruzsinszky and Ladich 1998;Platydoras armatulus -Ladich 1997;doradids -Knight and Ladich 2014) and croakers (male Cynoscion regalis - Connaughton et al 2000;Micropogonias furnieri -Tellechea et al 2010a; Pogonias cromis both sexes - Tellechea et al 2010b). A lack of a correlation between dominant frequency and size was reported in five out of six catfish species, but explained by the small size range of individuals recorded (Ladich 1997).…”

Insight into biting diversity to capture benthic prey in damselfishes (Pomacentridae)

“…It was first highlighted that the "mechanism involving the cerato-mandibular ligament" (hereafter, c-md mechanism) is used during acoustic communication in damselfishes, the sound being produced by an oral-teeth collision (Colleye and Parmentier, 2012;Parmentier et al, 2007). It was later illustrated that the same mechanism is also used during feeding (Olivier et al, 2015.…”