Learning to anticipate mate presence shapes individual sex roles in the hermaphroditic pond snail, Lymnaea stagnalis.

Despite being simultaneously male and female, hermaphrodites may still need to assume the male or female sexual role in a mating encounter, with the option to swap roles afterwards. For the great pond snail, Lymnaea stagnalis, deciding which sexual role to perform has important consequences, since sperm transfer and male reproductive success can be decreased. We hypothesised that detecting cues that indicate a possible mating encounter could help them to adapt their mating behaviour. Therefore, we experimentally assessed whether signalling the presence of a conspecific with an odour can affect the sexual role of Lymnaea stagnalis. The results showed that learning resulted in either an increased ability to mate as a male or in faster mating compared to the control group. These findings reveal that learning shapes the mating dynamics of Lymnaea stagnalis, thus showing that cognitive processes not only affect mating in separate-sexed species but also in hermaphrodites.