An in vivo electrophysiological study of mating behaviour in the snail Helix aspersa

Abstract

Summary The mating behaviour of the garden snail Helix aspersa consists of introductory behaviour, dart shooting and copulation. Earlier electrophysiological, morphological and immunocytochemical studies indicated that mating behaviour of this simultaneous reciprocal hermaphrodite is under control of the neurons of the mesocerebrum. With the use of implanted fine wires, in vivo recordings and stimulation of the right mesocerebrum were performed. The recorded neurons showed increased activity upon tactile stimulation of certain skin areas, during courtship and some also during copulation. Electrical stimulation of the right mesocerebrum evoked a gradual eversion of the genital pore. By combining this electrical stimulation with tactile stimulation of the everted genital pore, penial eversion and sometimes dart shooting could be evoked. The injection of APGWamide, a neuropeptide involved in the control of mating in other molluscs, caused an eversion of the genital pore resembling that seen in nature. FMRFamide has been suggested to be responsible for dart shooting, but its injection had no obvious effect. It is concluded that the mesocerebrum, with APGWamide as an important neuropeptide, has a central role in the execution of mating behaviour, but that other areas of the central nervous system might also be involved.