Electric organ discharges and near-field spatiotemporal patterns of the electromotive force in a sympatric assemblage of Neotropical electric knifefish

• Published in: Journal of physiology, Paris Vol. 110; no. 3; pp. 164 - 181
• Main Authors: Waddell, Joseph C., Rodríguez-Cattáneo, Alejo, Caputi, Angel A., Crampton, William G.R.
• Format: Journal Article
• Language: English
• Published: France Elsevier Ltd 01.10.2016
• Subjects: Amazon; Animals; Brachyhypopomus; Cloaking; Communication; Electric organ; Electric Organ - physiology; Electrogenesis; Electromagnetic Phenomena; Electroreception; Gymnotiform; Gymnotiformes - physiology; Hypopomidae; Rivers; Tropical Climate; PSD; emf-EOD; PPF; ht-EOD; Electric organ; EO; FDFT; Electroreception; Electrogenesis; Hypopomidae; Cloaking; Gymnotiform; Brachyhypopomus; FFT; EOD; Amazon; Communication
• ISSN: 0928-4257; 1769-7115; 1769-7115
• DOI: 10.1016/j.jphysparis.2016.10.004

•High diversity of head-to-tail electric organ discharges (EODs) among nine congeners.•High interspecific diversity of the electromotive force EOD (emf-EOD) pattern.•Rostro-caudal functional specialization of the electric organ is documented.•Emf-EOD pattern appears in some cases to be species and/or sex specific.•Data support an active electroreception role for ampullary electroreceptors. Descriptions of the head-to-tail electric organ discharge (ht-EOD) waveform – typically recorded with electrodes at a distance of approximately 1–2 body lengths from the center of the subject – have traditionally been used to characterize species diversity in gymnotiform electric fish. However, even taxa with relatively simple ht-EODs show spatiotemporally complex fields near the body surface that are determined by site-specific electrogenic properties of the electric organ and electric filtering properties of adjacent tissues and skin. In Brachyhypopomus, a pulse-discharging genus in the family Hypopomidae, the regional characteristics of the electric organ and the role that the complex ‘near field’ plays in communication and/or electrolocation are not well known. Here we describe, compare, and discuss the functional significance of diversity in the ht-EOD waveforms and near-field spatiotemporal patterns of the electromotive force (emf-EODs) among a species-rich sympatric community of Brachyhypopomus from the upper Amazon.