Lemon or Grove snail Cepaea nemoralis | |
---|---|
Cepaea nemoralis | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Heterobranchia |
Order: | Stylommatophora |
Family: | Helicidae |
Genus: | Cepaea |
Species: | C. nemoralis |
Binomial name | |
Cepaea nemoralis | |
Synonyms | |
|
The grove snail, brown-lipped snail or lemon snail (Cepaea nemoralis) is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc. [3]
It is one of the most common large species of land snail in Europe, and has been introduced to North America.
Cepaea nemoralis is the type species of the genus Cepaea. [5] It is used as a model organism in ecological genetics, including in citizen science projects. [6] [7]
Cepaea nemoralis is among the largest and, because of its bright colouration, one of the best-known snails in Western Europe. [6] The colour of the shell is highly variable; it ranges from brown, through pink, to yellow or even whitish, with or without one to five dark-brown bands. [8] Names for many colour variants were coined in the nineteenth century but this system has been replaced by an independent scoring of shell colour and the presence/absence and fusion of individual bands numbered 1 to 5. [9]
The thickened and slightly out-turned apertural lip of adults is usually dark brown, but can be white in some regions. [10] The umbilicus is closed in adults but narrowly open in juveniles. [8] The shell surface is semi-glossy. An adult shell consists of 4½–5½ whorls, with a width of 18–25 mm and a height of 12–22 mm. [8]
Cepaea nemoralis is closely related to Cepaea hortensis. They share much the same habitat and exhibit a similar range of shell colours and banding patterns. Cepaea nemoralis tends to grow larger, but usually the species can most easily be recognised by the colour of the lip of adult shells. In a high proportion of regions, C. nemoralis consistently has a dark-brown lip to its shell, whilst C. hortensis has a white lip. [10]
In areas where lip colour is variable, dissection is necessary. A cross-section of the love dart of C. nemoralis shows a cross with simple blades, whereas that of C. hortensis has bifurcated blades. The mucus gland has 3 or fewer branches in C. nemoralis, but 4 or more in C. hortensis. [12]
Two superficially similar species Caucasotachea vindobonensis and Macularia sylvatica both have a lip that is brown near the columella becoming pale towards the suture, and they have fine growth ridges on the shell whereas in both Cepaea species it is smooth. Also, M. sylvatica is distinct in having a small blunt tooth in its aperture, whilst the lowest brown band on the shell of C. vindobonensis lies noticeably closer to the columella than in Cepaea. [13]
Cepaea nemoralis is highly polymorphic in shell colour and banding. The background colour of the shell varies along a continuum from brown through pink to yellow and sometimes almost white. [14] Additionally the shells can be with or without dark bands. The bands vary in intensity of colour, in width and in number, from zero to five. The genetics underlying this variation is extensively understood and is shared with C. hortensis. [10]
The polymorphism has also been intensely studied for its evolution and ecology. For instance, in stable habitats shells tend to be darker in woodland than in open habitats. [15] The explanation might be camouflage or climatic selection: paler, more reflective colours in sunny environments reduce water loss and overheating. Climatic selection can also explain why yellow shells are more common in the south. [6]
Another question is why the variation persists, usually even within a locality. Researchers have variously argued that the cause is random genetic drift and founder effects, different selection pressures in different areas with mixing by migration, and balanced polymorphism. Balanced polymorphism could arise when a predator like the song thrush develops a 'search image' for the commonest morph, so that the rarer morphs are less likely to be predated. Natural selection would then favour a diversity of colours and patterns as an antipredator adaptation. Most probably, the polymorphism has multiple causes. [10] [16]
The native distribution of C. nemoralis is from Western and Northern Europe to Central Europe, but it has been spreading eastwards especially over the last few decades. [17] [18] Thus it is known from most of the Iberian Peninsula, [19] France, Great Britain, Ireland, Belgium, the Netherlands, Germany, Denmark, southern Sweden and Norway, Switzerland, Austria, the Czech Republic, [20] [21] Hungary, Bosnia, Croatia, and the northern half of Italy. [8] [22] In Central and Eastern Europe it has spread particularly along the Baltic coast (e.g. in Poland, [18] Latvia, Estonia, southern Finland, [23] the east coast of Sweden) [24] but also now elsewhere in Poland, [18] and in Ukraine, Belarus and Russia. [25] In Slovakia it was still known only from a single garden centre by 2020. [26]
At the northern edge of its range,C. nemoralis is rare and scattered in northern Scotland, where it has been introduced. [8] It is not found in the Hebrides, Orkney or Shetland. [8] It seems to have been affected by air pollution and soil acidification in some parts of England. [8]
Starting in 1857, there have been multiple introductions to North America, where it now occurs widely in Canada (from British Columbia to Newfoundland; in Ontario it is a pest of vineyards) and in the north-eastern part of the US, with further occurrences further south (e.g. California, Colorado, Texas and South Carolina). [27] [28] [29]
Both in America and Eastern Europe it is known that some introductions have been deliberate. [28] [25]
The range of C. hortensis mostly overlaps that of C. nemoralis but extends further north and less far south. [12]
This is a very common and widespread species in Western Europe, occupying a wide range of habitats from coastal dunes to woodlands with full canopy cover, including gardens and abandoned land. [6] In Eastern Europe, where it is a new arrival, it has turned up particularly in urban areas and other disturbed habitats. [18] It can be found up to an altitude of 1600 m in the Alps, [30] 1800 m in the Pyrenees, 900 m in Wales, 600 m in Scotland. [8] Density of adults is often of the order of 2 per square metre. [31]
This species feeds mainly on dead or senescent plants. [6] [8] It prefers broad-leaved plants over grasses. [32] Although mostly not a pest of crops, [8] it can be a nuisance in vineyards because it is inadvertently picked with the grapes. [33]
Like all pulmonate land snails, it is a hermaphrodite, and this species must mate to produce fertile eggs. [6] Mating tends to be concentrated in late spring and early summer, though it can continue through the autumn. [6] The snails may store the sperm they receive from their partner for some time, and individual broods can have mixed paternity. [6] In Britain it lays clutches of 30–50 (in France 40–80) oval eggs between June and August (in France May–October, in W France until November). [8] The size of the egg is 3.1 × 2.6 mm [34] or egg diameter can be 2.3–3.0 mm. [8] Juveniles hatch after 15–20 days. [8]
This snail is comparatively slow-growing, taking 1 to 3 years to develop from an egg to a breeding adult. [35] The life-span for this species is up to seven or eight years, with the annual survival rate of adults about 50% (= 3% over five years, older adults suffer higher mortalities). [8] In winter, the snails may hibernate, but can become active again during warm spells. [6]
Cepaea nemoralis is known experimentally to be a host for Angiostrongylus vasorum . [36] Predators of Cepaea nemoralis include the song thrush (Turdus philomelos).
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative phenotypes, in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population.
Balancing selection refers to a number of selective processes by which multiple alleles are actively maintained in the gene pool of a population at frequencies larger than expected from genetic drift alone. Balancing selection is rare compared to purifying selection. It can occur by various mechanisms, in particular, when the heterozygotes for the alleles under consideration have a higher fitness than the homozygote. In this way genetic polymorphism is conserved.
An interactor is a person who interacts with the members of the audience.
Arthur James Cain FRS was a British evolutionary biologist and ecologist. He was elected a Fellow of the Royal Society in 1989.
The white-lipped snail or garden banded snail, scientific name Cepaea hortensis, is a large species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Helicidae. The only other species in the genus is Cepaea nemoralis.
Heliciculture, commonly known as snail farming, is the process of raising edible land snails, primarily for human consumption or cosmetic use. The meat and snail eggs a.k.a. white caviar can be consumed as escargot and as a type of caviar, respectively.
Ecology and evolutionary biology is an interdisciplinary field of study concerning interactions between organisms and their ever-changing environment, including perspectives from both evolutionary biology and ecology. This field of study includes topics such as the way organisms respond and evolve, as well as the relationships among animals, plants, and micro-organisms, when their habitats change. Ecology and evolutionary biology is a broad field of study that covers various ranges of ages and scales, which can also help us to comprehend human impacts on the global ecosystem and find measures to achieve more sustainable development.
Helicidae is a large, diverse family of western Palaearctic, medium to large-sized, air-breathing land snails, sometimes called the "typical snails." It includes some of the largest European land snails, several species are common in anthropogenic habitats, and some became invasive on other continents. A number of species in this family are valued as food items, including Cornu aspersum the brown or garden snail, and Helix pomatia. The biologies of these two species in particular have been thoroughly studied and documented.
Arianta arbustorum, sometimes known as the copse snail, is a medium-sized species of pulmonate land snail in the family Helicidae.
Caucasotachea vindobonensis is a large species of air-breathing land snail, a terrestrial pulmonate gastropod in the family Helicidae.
Arion distinctus is a species of air-breathing land slug in the family Arionidae, sometimes known as the roundback slugs. It is a terrestrial pulmonate gastropod mollusc. Several vernacular names exist, but it is unclear if they are much in use: brown soil slug, common garden slug, darkface arion, Mabille's orange-soled slug, April slug.
Cepaea is a genus of large air-breathing land snails, terrestrial pulmonate gastropod molluscs in the family Helicidae. The shells are often brightly coloured and patterned with brown stripes. The two species in this genus, C. nemoralis and C. hortensis, are widespread and common in Western and Central Europe and have been introduced to North America. Both have been influential model species for ongoing studies of genetics and natural selection. Like many Helicidae, these snails use love darts during mating.
Amphidromus is a genus of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Camaenidae. The shells of Amphidromus are relatively large, from 25 mm (0.98 in) to 75 mm (3.0 in) in maximum dimension, and particularly colorful. During the 18th century, they were among the first Indonesian land snail shells brought to Europe by travelers and explorers. Since then, the genus has been extensively studied: several comprehensive monographs and catalogs were authored by naturalists and zoologists during the time period from the early 19th to the mid 20th centuries. Modern studies have focused on better understanding the evolutionary relationships within the group, as well as solving taxonomic problems.
Theba pisana, common names the white garden snail, sand hill snail, white Italian snail, Mediterranean coastal snail, and simply just the Mediterranean snail, is an edible species of medium-sized, air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Helicidae, the typical snails.
A love dart is a sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are both formed and stored internally in a dart sac. These darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place. Darts are quite large compared to the size of the animal: in the case of the semi-slug genus Parmarion, the length of a dart can be up to one fifth that of the semi-slug's foot.
Arion circumscriptus, common name brown-banded arion, is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Arionidae. It is commonest in woodland, occurring across most of Europe, except for more southern regions, and is also widespread in North America. It has been argued that A. circumscriptus is best considered a colour morph of Arion fasciatus.
Apaturris expeditionis is a species of sea snail in the family Borsoniidae.
Macularia sylvatica is a medium-sized species of air-breathing dextral land snail, a terrestrial pulmonate gastropod mollusc in the family Helicidae. It was once seen as a close relative of the grove snail, but does in fact not belong to the genus Cepaea at all.
This article includes public domain text from the reference [8] and CC-BY-2.5 text from the reference [6]