The role of gastropod pedal mucus in locomotion

Abstract

Gastropods move using a single appendage—the foot. For many gastropods the power for locomotion is provided by muscular waves moving along the ventral surface of the foot1–3, the force of these waves being coupled to the substratum by a thin layer of pedal mucus. This mucus acts as a glue, allowing the animal to adhere to the substratum on which it crawls2,3. This adhesive ability is advantageous, particularly to animals (such as limpets and certain snails) which live in intertidal or arboreal habitats where the forces of waves and gravity must be resisted while the animal forages. However, the adhesiveness of the pedal mucus presents the animal with a problem. How can an animal with only one foot walk on glue? This question was studied using as an example the terrestrial pulmonate slug, Ariolimax columbianus, and locomotion is found to depend on the unusual mechanical properties of the pedal mucus.