Werneyer, Martin and Kramer, Bernd (2005) Electric signalling and reproductive behaviour in a mormyrid fish, the bulldog Marcusenius macrolepidotus (South African form). Journal of Ethology 23 (2), pp. 113-125.
Bulldog fish (Marcusenius macrolepidotus) generate short (<1 ms) electric-organ discharges (EODs), separated by much longer and highly variable interdischarge intervals (IDIs). We observed overt behaviour and electrical
activity during reproductive behaviour in a male and in
a female bulldog, and identified IDI patterns with putative
signal functions. In contrast to Pollimyrus adspersus and
Pollimyrus isidori, in which an elaborate and extended
courtship precedes spawning proper, our fish started spawning almost immediately when we allowed the female to
enter the male’s territory. The male did not construct a nest, and neither parent provided parental care. The male
showed very little aggression towards the intruding female.
Fish spawned in bouts near the male’s hiding place, and eggs were scattered by the female’s vigorous tail flips as she left the spawning site, only to return shortly thereafter. During spawning bouts, both fish generated highly stereotyped IDI patterns: the male generated a series of IDIs gradually decreasing from about 200 ms to about 55 ms that was abruptly terminated by a long IDI. The female generated a series of relatively regular IDIs (about 54 ms) that was followed by a marked increase in IDI duration (the probable time of spawning). Finally, a sharp decrease in IDIs to about 20 ms accompanied the female’s sudden escape from the spawning site. In between spawning bouts, both fish generated series of very short IDIs (high discharge rate, HD) that alternated abruptly with very low-rate inter-HD activity (especially in the male). IDIs as short as 9 ms (male) or 11 ms (female) occurred during HD displays. No visible aggression, in fact very little overt behaviour, occurred during these HD displays in both fish. Agonistic interactions between male and female, outside a reproductive context, were similar to those previously described in male pairs, including overt behavioural patterns such as parallel swimming,
antiparallel display and attack, as well as HD displays.
When not interacting, fish did not generate HD displays. We
suggest the HD display is a communication signal in both
reproductive and agonistic contexts.
|Institutions:||Biology, Preclinical Medicine > Institut für Zoologie > Verhaltensbiologie und Verhaltensphysiologie (Prof. Dr. Bernd Kramer)|
|Keywords:||Reproduction; Spawning; Mormyrids; Electrocommunication; Agonistic|
|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:||06 Dec 2006|
|Last Modified:||13 Mar 2014 09:41|