Inducible phenotypic plasticity of the radula in Lacuna (Gastropoda: Littorinidae)

The radula is the major feeding organ of most gastropods and is a key taxonomic feature for many species. I demonstrate that two species of snail in the genus Lacuna Turton, 1827 (Gastropoda: Littorinidae) produce differently shaped radular teeth when fed different foods, displaying intraspecific variability as extreme as would usually be considered to define different species. The new tooth morphology is produced on the non-feeding end of the constantly regenerating radula, and is thus different from use-induced feeding morphologies seen in arthropods or vertebrates. Tooth shape in Lacuna is phenotypically plastic, inducible with different food conditions, and reversible within an individual's lifetime, allowing rapid response to new environmental conditions.