Helicodonta obvoluta

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Helicodonta obvoluta is a small air-breathing land snail found across much of Europe. It belongs to the family Helicodontidae and is often called the “cheese snail” because its shell looks a bit like a wheel of cheese.

Conservation status: Least Concern.

Description
- Shell: dark brown, flat on top with a very slightly sunken spire and a wide umbilicus. The opening (lip) is white and slightly thickened. Shell diameter is about 10–15 mm and height about 5–7 mm. Juveniles may have hair on the shell (about 1 mm long), but older snails often lose the hairs.
- Body weight of an adult snail is around 0.41 g.
- Unlike many related snails, it has no love darts.

Life and behavior
- Lifespan: about 2–3 years.
- Activity: mainly from April to November, especially early morning and at night.
- Mating lasts 2–3 hours.
- Reproduction occurs twice a year: spring (April–June) and autumn (August–October).
- Eggs are laid in rotten wood, in clusters of 9–27, and are protected by a mucus layer.
- Incubation is about 2–4 weeks. Hatchlings reach maturity after roughly 4–20 months. The spring generation may mature in the same year, while the autumn generation overwinters as juveniles.

Habitat and distribution
- Lives mostly near and inside fallen tree trunks, which provide egg-laying sites, food, daytime shelter, and winter refuges.
- In milder, wetter climates, it can also spend winter in leaf litter.
- Its main distribution covers much of Europe: from northwestern Spain through France, Switzerland, Liechtenstein, Belgium, Luxembourg, the Netherlands, parts of Germany and Austria, across Central Europe to the Czech Republic, Slovakia, Poland, Hungary, Slovenia, Croatia, Italy, Bosnia and Herzegovina, and Serbia.
- Isolated populations exist in southeastern England and northern Germany.
- The status of populations in Albania, North Macedonia, and Greece is unclear; some classify them as a separate species (Helicodonta albanica), while others treat them as a subspecies of H. obvoluta.