Meeting Abstract
P1.4 Saturday, Jan. 4 15:30 Encoding of species-specific waveform of electric fish signals in the amplitude envelopes created by social interactions PETZOLD, J.M.*; SMITH, G.T.; Indiana University – Bloomington; Indiana University – Bloomington jpetzold@indiana.edu
Apteronotid weakly electric fish use weak electric fields for communication. The frequency and the waveform of the electric organ discharge (EOD) vary substantially across species and may serve as species-identifying signals (Turner et al., 2007). Numerous studies have examined how fish determine the EOD frequency of other fish by decoding the beat pattern that is created as the EODs move in and out of phase with each other. We examined how EOD waveform is encoded in the amplitude modulations (envelopes) created by the interacting EODs of signalers and receivers. We simulated social interactions by using recordings of weakly electric fish that vary substantially in degree of waveform complexity. Our results show that EOD waveforms that were more harmonically complex also produced envelopes that were more harmonically complex. However, the relationship between the harmonic content of EOD waveform and the envelope was not linear. Thus information about EOD waveform can be extracted from the amplitude envelope, but subtle variation in EOD waveform may be difficult to detect. Weakly electric fish also modulate the frequency and amplitude of the EOD on short timescales to produce chirps that create abrupt disruptions in the envelope. We used an auto-correlation algorithm to quantify conspicuousness of chirps on envelopes across species. We found that chirps vary in the degree to which they disrupt the envelope. We will use this approach to assess how EOD frequency and waveform influence the coding of chirps in the amplitude envelope across species with diverse signals. This comparative approach will provide insight into how different signal parameters co-evolve in relation to the encoding abilities of the electrosensory system. Supported by NSF IOS 0950721.
