Function of electrocommunication signals in aggression and courtship of the Gymnotiform fish Apteronotus leptorhynchus

• Applicant: Professor Dr. Jan Benda
• Subject Area: Sensory and Behavioural Biology ; Cognitive, Systems and Behavioural Neurobiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 501755140

Weakly-electric fish are an exotic but successful model organism in the neurosciences at the interface of neuroethology, computational neuroscience, neuro­physiology, and evolution. Despite more than 60 years of detailed research on electrosensory processing and electrocommunication, we know surprisingly little about the behavioral significance and statistics of natural electrosensory stimuli the electrosensory system evolved to. Our technological developments now allow to track these nocturnal fish and at the same time record their electrocommunication signals without tagging by recording their electric fields with multi-electrode arrays. This technique opens, for the first time, a window into the secret nocturnal lives of these fascinating fishes. Our recent field work on Apteronotus rostratus in Panamá using a 54-electrode array, has revealed unexpected mismatches between electrosensory scenes during courtship and the tuning of electroreceptive neurons as well as a much sparser use of electrocommunication signals in aggression contexts between males compared to laboratory settings. This field study has demonstrated the high potential of the electrode-array technique in revealing the usage and meaning of electrocommunication signals.We propose to improve and employ this promising technique to thoroughly research various types of electrocommunication signals in the context of aggression and courtship of the gymnotiform electric fish Apteronotus leptorhynchus, a close relative to A. rostratus. In three work packages of increasing complexity we bridge from well controlled and constrained experiments in the laboratory to natural behaviors recorded in natural habitats. The central methodological aspect of the proposal is the improvement of the analysis algorithms for multi-electrode arrays with the aim of a versatile system that can be easily used by our collaborators. Re-analyzing our data from staged competition experiments we improve our algorithms for detecting electrocommunication signals and assess their role in negotiating access to shelter. At the core of the proposal are a series of breeding experiments in large tanks where we investigate the role of various types of communication signals in changing environmental and social contexts. Based on the insights and methods gained in the laboratory experiments we are then prepared to analyze existing data sets of freely behaving fish recorded in natural habitats where the fish evolved. The proposed project will result in novel insights of unprecedented detail into the the communication behaviors and associated sensory scenes of a nocturnal Teleost species.

• DFG Programme: Research Grants