Acoustic diversity in Lake Malawi's rock-dwelling cichlids

The cichlids of Lake Malawi are one of the world's most species rich and phenotypically diverse groups of extant vertebrates. The extraordinary variability of this group's color patterns, reproductive behaviors, and trophic morphologies are well documented. More recently, an additional axis of phenotypic diversity has been identified. Lake Malawi cichlids have been shown to use species-specific acoustic communication in both aggressive and reproductive encounters. However, documentation of acoustic signals used by this group is limited to a small number of taxa observed within the confines of the laboratory. This study examines the acoustic signals produced by six species spanning four genera of rock-dwelling cichlids recorded in their natural habitat, the shallow waters surrounding Thumbi West Island, Lake Malawi. Four acoustic parameters were quantified and compared between species: trill duration, number of pulses per trill, pulse duration, and pulse period. Using these characteristics, sympatric species within the genus Maylandia were easily distinguished. Furthermore, a comparison of this data to previously published acoustic data reveals possible geographic dialects within species.