Summary
The tropical South American teleost Eigenmannia lineata showed a spontaneous preference for the female type, compared with the male type, of its sexually dimorphic, weak-electric organ discharge (EOD). Female and male EODs differ in waveform and harmonic content. An isolated fish was simultaneously stimulated with digitally synthesized “natural” male and female EODs of equal peak-to-peak amplitudes, at ±35 Hz frequency difference centered on its stable resting discharge frequency. The stimulus dipoles were arranged symmetrically to the right and left of the fish's hiding place. All stimulus conditions were permuted at random sequence. Among 11 fish tested, 8 showed a statistically significant preference for one stimulus, the female type, as measured by the amount of time a fish spent close to a stimulus dipole (P<0.05 in each fish, two-tailed). Thus female EODs rather than male EODs were more attractive to adult and juvenile fish of both sexes. It was also concluded that E. lineata is capable of discriminating female from male EODs by a complex sensory capacity requiring neither amplitude nor frequency cues. The EOD waveform changed very little within the ecological range of water conductivities (approximately 10–100 μS·cm-1); the P/N-ratio (a waveform character based on zerocrossing intervals) depended only weakly, but significantly, on conductivity (negative correlation in all four fish). Also, the effect of temperature on EOD waveform was very weak: Q 10-values of the P/N-ratio were below but close to 1 in all fish (27±5°C). Thus, it can be concluded that the EOD waveform is remarkably stable within widely changing conditions-even beyond the variation found in the field-and is therefore potentially useful as a social cue.
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References
Bell CC, Bradbury J, Russell CJ (1976) The electric organ of a mormyrid as a current and voltage source. J Comp Physiol 110:65–88
Bennett MVL (1968) Neural control of electric organs. In: Ingle D (ed) The Central Nervous System and Fish Behavior. University of Chicago Press, Chicago, pp 147–169
Bennett MVL (1971) Electric organs. In: Hoar WS, Randall DJ (eds) Fish Physiology, vol V. Academic Press, London New York, pp 347–491
Bennett MVL, Grundfest H (1961) Studies on the morphology and electrophysiology of electric organs. III. Electrophysiology of electric organs in mormyrids. In: Chagas C, Paes de Carvalho A (eds) Bioelectrogenesis. Elsevier, Amsterdam, pp 113–135
Bratton B, Kramer B (1988) Intraspecific variability of the pulse-type discharges of the electric fishes, Pollimyrus isidori and Petrocephalus bovei (Mormyridae, Teleostei), and their dependence on water conductivity. Exp Biol (in press)
Cochran WG, Cox GM (1957) Experimental Designs, 2nd edn. Wiley & Sons, New York
Enger PS, Szabo T (1968) Effect of temperature on discharge rates of the electric organ of some gymnotoids. Comp Biochem Physiol 27:625–627
Furch K (1984) Water chemistry of the Amazon basin: The distribution of chemical elements among freshwaters. In: Sioli H (ed) The Amazon. Limnology and landscape ecology of a mighty tropical river and its basin. Junk Publishers, Dordrecht Boston Lancaster, pp 167–199
Gottschalk B (1981) Electrocommunication in gymnotoid wave fish: significance of a temporal feature in the electric organ discharge. In: Szabo T, Czéh G (eds) Sensory physiology of aquatic lower vertebrates. Adv Physiol Sci, vol 31. Pergamon Press/Akadémiai Kiadó, Budapest, pp 255–277
Hagedorn M, Heiligenberg W (1985) Court and spark: electric signals in the courtship and mating of gymnotoid fish. Anim behav 33:254–265
Heiligenberg W (1986) Jamming avoidance responses: model systems for neuroethology. In: Bullock TH, Heiligenberg W (eds) Electroreception. Wiley & Sons, New York, pp 613–649
Heiligenberg W, Altes RA (1978) Phase sensitivity in electroreception. Science 199:1001–1004
Hopkins CD (1974a) Electric communication: functions in the social behavior of Eigenmannia virescens. Behaviour 50:270–305
Hopkins CD (1974b) Electric communication in the reproductive behavior of Sternopygus macrurus. Z Tierpsychol 35:518–535
Hopkins CD, Bass AH (1981) Temporal coding of species recognition signals in an electric fish. Science 212:85–87
Kramer B (1985) Jamming avoidance in the electric fish Eigenmannia: harmonic analysis of sexually dimorphic waves. J Exp Biol 119:41–69
Kramer B (1987) The sexually dimorphic jamming avoidance response in the electric fish Eigenmannia (Teleostei, Gymnotiformes). J Exp Biol 130:39–62
Kramer B, Kirschbaum F, Markl H (1981) Species specificity of electric organ discharges in a sympatric group of gymnotoid fish from Manaus (Amazonas). In: Szabo T, Czéh G (eds) Sensory physiology of aquatic lower vertebrates Adv Physiol Sci, vol 31. Pergamon Press/Akadémiai Kiadó, Budapest, pp 195–219
Kramer B, Westby GWM (1985) No sex difference in the wave-form of the pulse type electric fish, Gnathonemus petersii (Mormyridae), Experientia 41:1530–1531
Kramer B, Weymann D (1987) A microprocessor system for the digital synthesis of pulsed or continuous discharges of electric fish (or animal vocalizations) Behav Brain Res 23:167–174
Kramer B, Zupanc GKH (1986) Conditioned discrimination of electric waves differing only in form and harmonic content in the electric fish Eigenmannia. Naturwissenschaften 73:679–680
Lissmann H (1958) On the function and evolution of electric organs in fish. J Exp Biol 35:156–191
Lissmann H (1961) Ecological studies on gymnotids. In: Chagas C, Paes de Carvalho A (eds) Bioelectrogenesis. Elsevier, Amsterdam, pp 215–226
Sachs L (1978) Angewandte Statistik Statistische Methoden und ihre Anwendungen. Springer, Berlin Heidelberg New York
Scheich H (1977a) Neural basis of communication in the high frequency electric fish, Eigenmannia virescens (jamming avoidance response). I. Open loop experiments and the time domain concept of signal analysis. J Comp Physiol 113:181–206
Scheich H (1977b) Neural basis of communication in the high frequency electric fish, Eigenmannia virescens (jamming avoidance response). II. Jammed electroreceptor neurons in the lateral line nerve. J Comp Physiol 113:207–227
Scheich H (1977c) Neural basis of communication in the high frequency electric fish, Eigenmannia virescens (jamming avoidance response). III. Central integration in the sensory pathway and control of the pacemaker. J Comp Physiol 113:229–255
Sioli H (1983) Amazonien. Grundlagen der Ökologie des grössten tropischen Waldlandes. Wissenschaftliche Verlagsgesellschaft, Stuttgart
Sioli H (1984) The Amazon and its main affluents: Hydrography, morphology of the river courses, and river types. In: Sioli H (ed) The Amazon. Limnology and landscap ecology of a mighty tropical river and its basin. Junk Publishers, Dordrecht Boston Lancaster, pp 127–165
Watanabe A, Takeda K (1963) The change of discharge frequency by a.c. stimulus in a weak electric fish. J Exp Biol 40:57–66
Westby GWM, Kirschbaum F (1981) Sex differences in the electric organ discharge of Eigenmannia virescens and the effect of gonadal maturation. In: Szabo T, Czéh G (eds) Sensory physiology of aquatic lower vertebrates. Adv Physiol Sci, vol 31. Pergamon Press/Akadémiai Kiadó, Budapest, pp 179–194
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Kramer, B., Otto, B. Female discharges are more electrifying: spontaneous preference in the electric fish, Eigenmannia (Gymnotiformes, Teleostei). Behav Ecol Sociobiol 23, 55–60 (1988). https://doi.org/10.1007/BF00303059
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DOI: https://doi.org/10.1007/BF00303059