ONTOGENY

The ontogeny of a behavior refers to the development of a behavior in a particular organism. It is a timeline of the behavior's development in one individual from the organism's birth to when the behavior ceases to develop. Very little research has been done on the ontogeny of dart-shooting behavior in H. aspersa. It is unknown when in the organism's lifecycle the snail becomes physically capable of dart shooting, the age at which the snail first performs the behavior, or whether the behavior changes as the organism develops.

A snail would have no need for the dart shooting behavior until it became sexually mature, however, so it can be surmised that the snail most likely would not perform the behavior until this point in its development. The average age of sexual maturity in H. aspersa varies from location to location. This is due to varying environmental conditions, as the snail life cycle is dependent upon the presence of adequate moisture. H. aspersa take about two years to reach sexual maturity in Southern California, while the same snails would take only 10 months to develop in South Africa (Koene et al. 2000). These variations in development would also affect the development of the dart-shooting behavior.


Photo courtesy of Ronald Chase at McGill University. Snail mating event with visible pierced dart (on right) and spermatophore injection.