Dissociation of sexual arousal and sexual proclivity in the garden snail, Helix aspersa

Sexual arousal (intensity of courtship) and sexual proclivity (tendency to court) in Helix aspersa can be reliably measured using externally observable correlates. Snails with sexual proclivity are significantly more likely to turn toward an anesthetized conspecific after contacting it than are sexually unreceptive snails. Sexual arousal can be inferred from the stage of a snail's genital eversion, which appears only during courtship. The higher the stage of the eversion, the shorter the time required to complete introductory courtship behavior and the higher the rate of successful copulation, the fewer the number of breaks and pauses during courtship, and the longer the time a snail will spend in contact with an anesthetized conspecific. Sexual proclivity has no effect on feeding or locomotory behavior; however, sexual arousal inhibits feeding and increases locomotor activity. Snails that were allowed daily contact with conspecifics required less time to complete introductory courtship behavior relative to snails that were isolated from conspecifics for 1 week. This suggests that daily contact increases sexual arousal. A greater percentage of isolated snails exhibited courtship behavior than did snails which had experienced daily conspecific contact. This suggests that isolation increases sexual proclivity. These differences indicate that sexual arousal is not merely due to an increase in sexual proclivity.