The central organisation of courtship and rivalry behaviour in Gryllus bimaculatus (deGeer) as revealed by lesions of abdominal connectives

Abstract

Behaviour is rooted in the organization and activity of an animal’s nervous system. As male crickets use their front wings for sound production, the neural circuits underlying singing had been suggested to be housed in the thoracic ganglia. However, systematic lesion experiments of the CNS demonstrated that the abdominal nervous system is essential for their calling song behaviour. As male crickets also generate a courtship and rivalry song, we explored which parts of the abdominal central nervous system control the underlying motor patterns. A combination of systematic lesions to the abdominal nerve cord and video recording of courtship and rivalry behaviour revealed that most components of male courtship and rivalry behaviour were not affected by the lesions, except for the generation of courtship song, rivalry song, and the male’s ability to copulate with the female. Any lesion to the abdominal nerve cord abolished copulations. Generation of courtship song initially failed when the connection to abdominal ganglion A6 was severed but in few males recovered after a week. For rivalry song production a central nerve cord extending to abdominal ganglion A4 was sufficient. These findings indicate that in the bispotted cricket the neural organization of courtship song is different from calling and rivalry song, while calling song and rivalry song might share a common network for generating the song patterns.