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Arianta arbustorum (Linnæus, 1758)
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Species name:
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Arianta arbustorum (Linnæus, 1758)
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Taxon name:
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Helix arbustorum Linnæus, 1758
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Originally described in:
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Linnæus, C. 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. - pp. [1-4], 1-824. Holmiæ. (Salvius).
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Distribution:
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NW and central Europe with Alps and Carpathians, E Pyrenees (Spain) to N Norway and Iceland, N Ireland, Kaliningrad, Estonia, Latvia, scattered to Serbia, Bulgaria and W Ukraine
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Diagnosis:
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Shell usually brown with numerous pale yellowish rows of spots and usually with a brown band
above the priphery, occasionaly yellowish, reddish or with greenish hue, weakly striated and
with fine spiral lines on the upper side, 5-5.5 convex whorls with deep suture, last whorl
slightly descending near aperture, aperture with prominent white lip inside, margin reflected,
umbilicus entirely covered by the reflected columellar margin.
The animal is usually black.
Shell shape globular in most present-day populations, but originally believed to have been depressed in the Pleistocene, before lowlands were invaded and shells became globular, re-invading mountain regions except some isolated spots among glaciers (Gittenberger 1991).
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Size:
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12-22 x 18-25 mm, locally variable
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Biology:
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Forests and open habitats of any kind, requires humidity, lives also in disturbed habitats (not in Ireland where it is restricted to old native woodland). May locally tolerate non-calcareous substrate, in N Scotland also on sandhills. In the Alps up to 2700 m, in Britain 1200 m, in Bulgaria 1500 m. Feeds on green herbs, dead animals and faeces.
If snails hatched more than 50 m distant from each other, they are considered isolated since they would not move more than 25 m (neighbourhood area 32-50 m), usually they move about 7-12 m in a year, mostly along water currents.
Reproduction usually after copulation, but self-fertilization is also possible, in France, Britain and Germany 30-50 eggs (diameter 2.5-3.3 mm) are laid between July and September in a yellowish opaque envelope, juveniles hatch after 15-25 days, maturity is reached with full shell size after 1-2 years, occasionally later, life span around 4 years, maximum age up to 14 years.
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Threatened:
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One of the most frequent species of land snails in Switzerland, can be very abundant, up to 20 adults per square meter. In Britain the species suffered slightly from intensive farming and the continuous destructions of suitable uncultivated refuges.
Rare in Ireland and Bulgaria.
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Family:
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Helicidae
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Higher group:
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Gastropoda
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Comments:
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Several subspecies are recognized by some authors.
References: Moquin-Tandon 1855: 123, Westerlund 1889: 147, Germain 1930: 226, Frömming 1954: 289, Damjanov & Likharev 1975: 375, Shilejko 1978: 311, Falkner 1990: 226, Gittenberger 1991, Baur 1993, Manganelli et al. 1995: 32, Turner et al. 1998: 360, Kerney 1999: 200, Falkner et al. 2001, Hubenov 2007, Irikov & Erőss 2008 (rare in Bulgaria), Welter-Schultes 2012: 578 (range map).
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