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Bug of the Month: Brown-lipped snail

Common name: Brown-lipped snail (also: Grove snail, Banded wood snail)

Latin name: Cepaea nemoralis

Taxonomy:
Kingdom Animalia
   Phylum Mollusca
      Class Gastropoda
         Order Stylommatophora
            Family Helicidae

 

brown lipped snail
Snails in general

Although snails are more closely related to octopi and squids than to insects and other arthropods, we have included them in our inventory because they are commonly-seen invertebrates on the Boston Harbor Islands and they live amongst the bugs!

Unlike arthropods, mollusk bodies are soft and unsegmented. Gastropods are a group of mollusks which include marine, freshwater, and terrestrial snails. All snails have a head, a muscular “foot” on the ventral side, and a dorsal hump which is usually encased in a hard shell. The air-breathing land snails, which make up the order Stylommatophora, have coiled shells (except for the shell-less slugs), and they can retract their entire body into these shells to protect themselves from predators or very dry conditions. Shells are made of calcium carbonate which is secreted by a tough layer of skin called the mantle. As the shell grows in size, more whorls are added to the spiral. Snails in the family Helicidae are medium to large in size, often with brightly colored shells, and are all of Eurasian origin. Helicids include common garden snails as well as the “escargot” consumed by humans.

diagrammed photo of the worls and brown lip

comparison of white- and brown-lipped snailsHow to identify brown-lipped snails

Brown-lipped snails are the largest snails on the Boston Harbor Islands, and their shells can reach a width of 20 to 25mm (¾ to 1 inch) as adults. Adult shells are made up of about 5 complete whorls in the spiral, and are very variable in color. Most have a background color of tan, yellow, or olive, with 0 to 5 dark brown bands. The brown lip that gives these snails their name refers to the flared margin around the opening of the shell. The color of the lip also separates the brown-lipped snail from its close relative, the “white-lipped” snail (Cepaea hortensis). Both species are found on the islands, and although the white-lipped snail tends to be slightly smaller, the color and shape of the shell can be confusingly similar with that of the brown-lipped snail. Unfortunately, immature (i.e., smaller) snails do not have lips on their shells, and so their species cannot easily be determined.

Where to find brown-lipped snails on the Boston Harbor Islands

We have found brown-lipped snails on many islands; you are likely to find this species in woodlands, shrublands, and meadows. Sites where vegetation is composting are good places to start the hunt. The brown-lipped snail is mostly active at night, but can be found in moist places (e.g., under rocks, logs, leaf litter) during the day. Sometimes they will crawl up a plant after feeding, stick themselves to it with some slime, and remain there until it’s time to get the next meal. Look for a shiny “slime trail” as evidence that a snail passed by recently!

2 views of a brown-lipped snail, lighter shellHow brown-lipped snails make a living

The brown-lipped snail is herbivorous and feeds largely on rotting plants, grasses, and shrubs. It is eaten by birds, invertebrate predators (beetles and others), and small mammals. As with almost all terrestrial snails, brown-lipped snails are hermaphroditic, meaning each snail has both male and female reproductive parts. During courtship, two brown-lipped snails will circle and shoot “love darts” [opens external site in new window] at each other. Later, the snails align themselves and sperm is exchanged through reproductive openings, which will later (sometimes months later) fertilize eggs in each snail. Eggs are laid in moist soil about two weeks after mating, and take several weeks to hatch. Brown-lipped snails reach adulthood in one to four years, and may live up to 9 years. In the winter, the snails bury themselves into the soil.

2 views of a brown-lipped snail, darker shellWhere in the world brown-lipped snails occur

Brown-lipped snails are native to Europe. Humans have helped them spread almost world-wide both accidentally, in the company of plants and soil, and purposefully, as food and ornaments.  Their first introduction to the United States was in 1857 by Dr. W. G. Binney, a zoologist specializing in the study of mollusks in New Jersey. They were subsequently introduced to other parts of the country (accidentally) and can now be found in at least 15 states. 

To learn more about brown-lipped snails (and snails in general)

On the web:

In print:

    Burch, J. B. 1962. How to know the Eastern land snails. William C. Brown Company Publishers, Dubuque, Iowa.

    Kerney, M.P. and R.A.D. Cameron. 1979. A field guide to the land snails of Britain and North-west Europe. William Collins Sons and Co. Ltd., Glasgow, Scotland.

    Whitson, M.  2005. Cepaea nemoralis (Gastropoda, Helicidae): the invited invader. Journal of the Kentucky Academy of Science 66: 82-88.