Werneyer, Martin and Kramer, Bernd (2006) Ontogenetic development of electric-organ discharges in a mormyrid fish, the bulldog Marcusenius macrolepidotus (South African form). Journal of Fish Biology 69 (4), pp. 1190-1201.
The emergence and development of the electric-organ discharge (EOD) in larvae and juvenile bulldog Marcusenius macrolepidotus was investigated. Larvae hatched 4–5 days after spawning, and the first EODs were recorded on days 9 and 10 at a standard length (LS) of c. 6·5 mm. The larval EOD waveform was virtually monopolar, with a strong head-positive phase followed by a weak head-negative phase of long duration. A small separate potential preceded the EOD by c. 1·6 ms (believed to represent postsynaptic potential from electrocyte stalks). In contrast to previous reports on Pollimyrus adspersus with its distinct larval and adult EODs, in M. macrolepidotus there was a gradual transformation of the larval into the adult EOD waveform. The transformation started at an LS of c. 17 mm (at an age of c. 40 days), first indications being a decrease in duration of the head-negative phase, and an increase of its peak amplitude relative to that of the head-positive phase. Still later, the weak postpotential of the adult EOD emerged on the rising edge of the head-negative phase. The transformation was nearly completed at an LS of c. 30 mm (at an age of c. 60 days). Evolutionary and behavioural consequences of this alternative path of EOD ontogeny are discussed.
|Institutions:||Biology, Preclinical Medicine > Institut für Zoologie > Verhaltensbiologie und Verhaltensphysiologie (Prof. Dr. Bernd Kramer)|
|Keywords:||development; electric-organ discharge; fish larvae; Mormyridae; ontogeny; reproduction|
|Subjects:||500 Science > 570 Life sciences|
500 Science > 590 Zoological sciences
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Deposited On:||14 Jul 2006|
|Last Modified:||20 Jul 2011 20:48|