Meeting Abstract

P2.10  Monday, Jan. 5  Sexually Dimorphic Communication Behaviors in Sternarchogiton nattereri FORMBY, K.J.*; HO, W.W.; TURNER, C. R. ; SMITH, G. T. ; University of Wisconsin – Whitewater; Indiana University; Indiana University; Indiana University formbykj06@uww.edu

The electrocommunication signals of electric fish differ across individuals, species, and sexes. Each individual emits an electric organ discharge (EOD) at a relatively stable frequency (EODf) that can serve as an indicator of sex or species. Individuals modulate their EOD, to produce chirps and gradual frequency rises (GFRs) that serve as social signals. Although EOD frequency, waveform, and modulations have been studied in many species (Turner et al. 2007; Hopkins, 1988; Kramer et al. 1981), sex differences in these behaviors have been studied in only four apteronotid species, three of which belong to a single genus, Apteronotus. To further examine species diversity in the sexual dimorphism of electrocommunication signals, we examined sex differences in EODs and chirping in Sternarchogiton nattereri. We recorded each fish while they were presented with an array of sinusoidal stimuli (+5Hz, 20Hz, 150hz) relative to the fishes EODf. These stimuli encompassed the species-typical range of EODf. S. nattereri responded robustly to playback stimuli. EODf, chirp duration, and chirp rate were sexually monomorphic. However, S. nattereri males produced chirps with a greater amount of frequency modulation than those of females. Combined with previous studies on sex differences of electric communication signals in other species, our data suggest that sex differences in chirp structure (FM and/or duration) are relatively widespread in apteronotids, but that the magnitude and/or direction of sex differences in EODf and chirp rate vary considerably across species.