Diversidade do repertório eletrocomunicativo de Microsternarchus cf. bilineatus Fernández Yépez, 1968 (Pisces: Gymnotiformes) durante a maturação sexual em cativeiro

Abstract

The electric fishes possess a sensorial and motor system, denominated Electrogenic and Electrosensory System, responsible for the detection and generation of electric fields. The Gymnotiforms from South and Central America possess especialized electric organs and electroreceptors used in active electrolocalization of objects and organisms and in inter and intraspecific social interaction. The knowledge of the diversity of electrocommunication has shown to be a good model for the study of the origin and adaptative meaning of behavior and communication: the variation of some physical properties related to the shape and temporal patterns of the electric organ discharge seem to be fundamental for the display of agonistic and reproductive behaviors. The main objective of this work was to characterize the diversity of electrocommunicative displays during sexual maturation of Microsternarchus cf. bilineatus. Therefore, with the obtained results it was possible to characterize the electric organ discharge of Microsternarchus cf. bilineatus as a pulse type discharge, with three distinct phases, with a frequency from 146Hz to 34Hz, and with a well defined circadian cycle. It was possible to establish sexual dimorfism in the frequency (greater in males ) and in the shape of the electric organ discharge (relative amplitude of phase III and relative duration of phase I greater in females). Finally, it was possible to identify and describe defense of territory and dominance behavior s related to high frequencies. With these results we can conclude that the characteristic modulations of the electrocommunicative repertory of Microsternarchus cf. bilineatus can be found, mainly, in the analysis of the shape of the electric organ discharge.