Abstract

The cavity-nesting darters Etheostoma nigripinne, Etheostoma crossopterum, and their hybrid (E. nigripinne × E. crossopterum) were found to produce sounds associated with reproduction. Males produced sounds during aggressive encounters and courtship activities. All three taxa produced nonpulsed sounds categorized as drums and shorter, usually pulsed, sounds categorized as knocks. In addition, E. nigripinne produced pulsed sounds referred to as purrs that differ from knocks in having a higher pulse number and rate. All sound types were made under both aggressive and courtship contexts by males of all three taxa. The dominant frequency and duration of sounds differed by sound type (drums, knocks, purrs) for all taxa. In addition, within the drum sound type, the dominant frequency differed between contexts (aggression vs courtship) and among taxa. Although sound production has been documented for numerous fish species, this is the first time sounds have been described for percids. The mechanism and role of sound production in darters has yet to be determined.