Snail Brown Garden, Helix aspersa
Kingdom: Animalia
Phylum: Mollusca
Class : Gastropoda
Order: Pulmonata
Superfamily: Helicoidea
Family: Helicidae
Genus: Helix
Species: H. aspersa
Scientific name: Helix aspersa
Synonyms: Cornu aspersum and Cantareus aspersus
Common name: Brown Garden Snail
Helix aspersas is an invasive alien snail with shells up to 32 mm in diameter and is originally from Europe and is, widespread in New Zealand. Active at night or during wet weather it is Slow moving, using a slime trail. It has a well developed sense of smell and /taste.
Each mature snail will mate several times in a single season and egg laying starts 3–6 days after first mating, but can occur within hours of subsequent matings.. Helix aspersa deposit their eggs into pockets in moist soil. These pockets are usually excavated by the snails themselves through movement of the head and anterior foot, though occasionally natural cavities will be used. After oviposition the nests are covered with soil and abandoned. The number of eggs in each clutch varies from 10 to 170. The incubation period of the eggs vary according to the relative humidity of the incubation environment.. The average is 13 to 19 days. The young hatchling snails remain in the nest for 1–16 days . During this time, cannibalism on sib eggs can occur.
There is concern of this snails effect indigenous biodiversity through selective feeding on foliage of herbaceous plants and the seedlings of a range of species, Helix aspersa represents a significant threat to natural processes of vegetation regeneration. Many of the introduced terrestrial molluscs brought with them to New Zealand a range of parasites, including mites, ciliate protozoa, microsporidia, and nematodes.. With increasing contact between the alien and indigenous species, there is potential for transmission of these parasites and pathogens to our indigenous fauna. This transmission has already occurred in the case of the parasitic mite Riccardoella limacum in urban areas and in Egmont National Park . Cantareus aspersus provides a reservoir of Riccardoella that is likely to infest sympatric indigenous species.
Helix aspersa snail on patrol 
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