Eobania vermiculata
Species of gastropod
From Wikipedia, the free encyclopedia
Eobania vermiculata also known as Helix vermiculata, common name the "chocolate-band snail", is a species of large, air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Helicidae, the true snails or typical snails.
| Eobania vermiculata | |
|---|---|
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| Two shells of the species showing apical and apertural views | |
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| An unusually dark, subadult live individual of Eobania vermiculata | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Stylommatophora |
| Family: | Helicidae |
| Genus: | Eobania |
| Species: | E. vermiculata |
| Binomial name | |
| Eobania vermiculata (O. F. Müller, 1774)[1] | |
| Synonyms | |
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Helix vermiculata O. F. Müller, 1774 | |
Eobania vermiculata is the type species of the genus Eobania.
Distribution
This species of large land snail is common in the Mediterranean area; its distribution ranges from eastern Spain to Crimea:
The nonindigenous distribution of Eobania vermiculata includes:
- This species has been introduced to southeastern Australia, where it is known as the chocolate-band snail.[4]
- One individual of this snail species was found living on a wall in Lewisham, London, England, in 2006.[5][6] It remains to be seen if a colony will establish itself or not.
- E. vermiculata has non-indigenous populations in Belgium, Germany, Hungary, the Netherlands, the US, Australia, Japan, South Africa, Egypt, Israel, Saudi Arabia, Jordan, and Iran.[7]
This species is already established in the US, and is considered to represent a potentially serious threat as a pest, an invasive species which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore, it has been suggested that this species be given top national quarantine significance in the USA.[8]
E. vermiculata is able to survive winters in the North-West European temperate zone, including Belgium and the Netherlands.[7]
Description
In this species the color of the shell is variable. The background color can be whitish to greenish yellow, and the shell often has darker coloured bands or spots.[3] The ventral side of the shell frequently has two brown bands and is whitish between the lowest band and the umbilicus.[3] The shell has 4–4.5 whorls.[3] The last whorl descends abruptly below the periphery of the shell.[3] The apertural margin is white, and is reflected (turned back) in adult shells; in juveniles this is true only on the columellar side.[3] The umbilicus is narrow and open in juveniles, only partly covered by the reflected columellar margin; in adult shells, however, the umbilicus is completely closed.[3]
The width of the shell is 22–32 mm; the height of the shell is 14–24 mm.[3]
In northern Greece, the variability within the populations of this species seems to be lower than in southern Greece (Gávdos Island: 24.5-33.5 m in diameter of adult shells, average 28–29 m, with no local variations in shell size).[3]
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Juveniles somewhat resemble the species Theba pisana (which also has a similar umbilicus); however Eobania vermiculata can be differentiated from that species by its much larger apex.[3]
Ecology
Eobania vermiculata live in a broad variety of habitats, usually in dry vegetation, mainly in the vicinity of the coast, and also in agricultural crops.[3] It is very common in Crete and lives on practically every small island in the south Aegean.[3]
In northern Greece copulation takes place after the first rainfalls in autumn.[3] These snails create and use love darts as part of their mating behavior. Around 70 eggs per snail are laid 20 days later.[3] The size of the egg is 4.1 × 3 mm.[9] Juveniles hatch shortly after and grow about 12–13 mm in diameter per year for 2 years (growth is usually restricted to February to June in northern Greece, in Crete this period ends already in May).[3] Maturity is reached after 2 years when the diameter reaches 25 mm, the umbilicus becomes closed and the apertural margin becomes reflected.[3] Snails reach 29–30 mm diameter in May/June of the second year in northern Greece (in April in Crete), reaching a maximum diameter (33 mm) may take 5 years or more, but mortality increases greatly after 2 years.[3]
About 20% of the snails in a population survive to lay eggs in the 3rd year; 5% of the snails lay eggs again in the 4th year.[3] The mortality rates decrease with age.[3] The animals hibernate (in northern Greece) or aestivate (in Crete), but juveniles and adults show differences in their behaviour.[3] Adults dig into the soil and build an epiphragm, while juveniles search protected places under stones or leaves of low plants.[3]
