- Grove snail
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Grove snail 
Cepaea nemoralis Conservation status NE[1]Scientific classification Kingdom: Animalia Phylum: Mollusca Class: Gastropoda (unranked): clade Heterobranchia
clade Euthyneura
clade Panpulmonata
clade Eupulmonata
clade Stylommatophora
informal group SigmurethraSuperfamily: Helicoidea Family: Helicidae Genus: Cepaea Species: C. nemoralis Binomial name Cepaea nemoralis
(Linnaeus, 1758)[2]The grove snail or brown-lipped snail (Cepaea nemoralis) is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc. It is one of the most common species of land snail in Europe and has been introduced to North America.
Cepaea nemoralis is the type species of the genus Cepaea.[3]
It is used as a model organism in citizen science projects.[4]
Contents
Description
Cepaea nemoralis is among the largest and because of its polymorphism and bright colours one of the most easily identified snails in Western Europe.[4] The color of the shell of Cepaea nemoralis is very variable, reddish, brownish, yellow or whitish, with or without dark brown colour bands.[5] Apertural lip usually dark brown, rarely white.[5] The umbilicus is narrow but open in juveniles, closed in adults.[5] For every colour variant names were established in the 1800s; this was later abandoned.[5] The surface of the shell is semi-glossy, and it has from 4½ to 5½ whorls.
The width of the shell is 18–25 mm.[5] The height of the shell is 12–22 mm.[5]
The animal is moderately slow and not very shy.[5] In Haus der Natur Cismar this species is used to demonstrate snail behaviour to children.[5]
Lateral view of the shell of Cepaea nemoralis.
Basal view of the shell of Cepaea nemoralis.Similar species:
- Cepaea vindobonensis is less intensively coloured.[5]
- Cepaea nemoralis differs from Cepaea hortensis usually by its dark lip.[5] In areas where lip colour is variable, dissection is necessary.[5] Cross-section of love darts shows a cross with simple blades, Cepaea hortensis has bifurcated blades.[5] Cepaea hortensis has 4 or more branches of body light with reddish or brownish hue, upper side often slightly darker, tentacles darker and 15 mm long.[5] Cepaea nemoralis is closely related to the white-lipped snail, Cepaea hortensis, and shares much the same habitat. The grove snail is usually the larger of the two species when mature, but the principal difference is that the adult grove snail almost always has a dark brown lip to its shell, whilst adults of Cepaea hortensis almost always have a white lip. However, this distinguishing feature is not entirely reliable, as there is at least one morph of the grove snail which also has a white lip. When the identity of an adult individual is questionable, and it is necessary to distinguish the two species, a dissection can be used in order to examine the anatomy: the structure of the love dart is quite different in the two species, as are the vaginal mucus glands.
Coloration
Main article: Polymorphism (biology)#Grove snailApart from the band at the lip of the shell, grove snails are highly polymorphic in their shell colour and banding. The background colour of the shell can sometimes be so pale as to be almost white; it can also be yellow, pink, chestnut through to dark brown, and the shells can be with or without dark bandings. The bands vary in intensity of color, in width and in total number, from zero up to a total of six.
These polymorphisms have been highly studied as part research in heredity and evolution. They are thought to act as camouflage to avoid predation from, for example, the Song Thrush, but also have implications for the body heat of the animal: darker shells heat up more quickly, with consequences for rates of metabolism and loss of moisture (crucial in snail locomotion). In particular, grove snails with dark brown appear to preferentially be found in dark woodlands, whilst snails with light yellow shells and thin banding are more commonly found in grassland.
Different coloration and banding of the shells of Cepaea nemoralis:
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without dark bandings
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with one band
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with more bands
Distribution
Cepaea nemoralisIts native distribution is from northern and western Europe to central Europe:[6]
Western Europe:
- Ireland[5]
- Great Britain. It is rare and scattered in northern Scotland and is is obviously introduced there.[5] (It does not live on the Hebrides, Orkney or Shetland.[5]) It seems to have been affected by air pollution and soil acidification in some parts of England.[5]
- France
- Netherlands
- Switzerland
Central Europe:
- Austria
- Germany
- in the east to northwestern Poland[5]
- Czech Republic - least concern (LC)[7]
- SW Hungary[5]
Southern Europe:
Northern Europe:
- in the north to southern Sweden[5]
Eastern Europe:
No doubt aided by human transport, it is a good colonizer, and is often found in gardens, parks and abandoned land in cities.[4] In eastern Europe it occurs in urban areas. More recently, the grove snail has been introduced to North America,[5] and has established itself in various places. Also in Venezuela.
The white-lipped snail has a similar range, but that species extends further north to border the Arctic.
Ecology
Mating
Love dart of Cepaea nemoralis
Grove snail shells on a Song Thrush 'anvil'It is a very common and widespread species in the Western Europe, occupying a very wide range of habitats from dunes along the coast to woodlands with full canopy cover.[4] It lives in shrubs and open woods in plains and highlands, dunes, cultivated habitats, gardens and roadsides.[5] It can be found up to 1200 m in the Alps, 1800 m in the Pyrenees, 900 m in Wales, 600 m in Scotland.[5]
It feeds mainly on dead or senescent plants.[4][5] It is not noxious to crops.[5]
Like most Pulmonate land snails, it is hermaphrodite and must mate to produce fertile eggs.[4] Mating tends to be concentrated in late spring and early summer, though it can continue through the autumn.[4] The snails often store the sperm they receive from their partner for some time, and individual broods can have mixed paternity.[4] In Britain is lays clutches of 30-50 (in France 40-80) oval eggs are laid between June and August (in France May-October, in W France until November).[5] The size of the egg is 3.1 × 2.6 mm[8] or egg diameter can be 2.3-3.0 mm.[5] Juveniles hatch after 15-20 days.[5] Maturity is reached after shell is fully grown, in France after 1 year.[5] It is comparatively slow-growing, usually taking three years to develop from egg to breeding adult.[4] Life-span is up to 7-8 years, annual survival rates at about 50 % (= 3 % in 5 years, older adults suffer higher mortalities).[5] In winter, the snails may hibernate, but can be active in warm spells.[4]
Parasites:
- Cepaea nemoralis it is known experimental (only experimental?)[verification needed] host for Angiostrongylus vasorum.[9]
Predators of Cepaea nemoralis include the Song Thrush Turdus philomelos and others.
References
This article includes public domain text from the reference[5] and CC-BY-2.5 text from the reference[4]
- ^ 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Cited 18 July 2007.
- ^ Linnaeus C. (1758). Systema naturae per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. pp. [1-4], 1-824. Holmiae. (Salvius).
- ^ "Genus summary for Cepaea". AnimalBase, last modified 23 December 2008, accessed 1 May 2011.
- ^ a b c d e f g h i j k Silvertown J., Cook L., Cameron R., Dodd M., McConway K. et al. (2011). "Citizen Science Reveals Unexpected Continental-Scale Evolutionary Change in a Model Organism". PLoS ONE 6(4): e18927. doi:10.1371/journal.pone.0018927.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al "Species summary for Cepaea nemoralis". AnimalBase, last modified 6 February 2011, accessed 1 May 2011.
- ^ Dvořák L., Honěk A. & Martínková Z. (2003). "The spread of Cepaea nemoralis (L.) populations in the Czech Republic". 2003 BCPC Symposiumproceedings No. 80: Slugs & snails: agricultural, veterinary & environmental perspectives: 99-102.
- ^ Juřičková L., Horsák M. & Beran L. (2001). "Check-list of the molluscs (Mollusca) of the Czech Republic". Acta Soc. Zool. Bohem. 65: 25-40.
- ^ Heller J. (2001). Life History Strategies. In: Barker G. M. (ed.). The biology of terrestrial molluscs. CABI Publishing, Oxon, UK, ISBN 0-85199-318-4. 1-146, cited page: 428.
- ^ Conboy G. A. (30 May 2000). "Canine Angiostrongylosis (French Heartworm)". In: Bowman D. D. (Ed.) Companion and Exotic Animal Parasitology. International Veterinary Information Service. Accessed 24 November 2009.
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