''Theba pisana'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s 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 land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

pulmonate Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the family

Helicidae Helicidae is a large, diverse family of small to large, air-breathing land snails, sometimes called the "typical snails." A number of species in this family are valued as food items, including ''Cornu aspersum'' (formerly ''Helix aspersa'') the b ...

, the typical snails. This species is native to the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

region, but it has become an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

in many other countries. ''Theba pisana'' is a well-known agricultural pest in numerous parts of the world. The shell color varies from white to yellow-brown with light brown spiral markings.

Distribution

The species is native to the

region. The type locality is Italy. The distribution of ''Theba pisana'' includes the Mediterranean region and adjacent Atlantic coasts from central Morocco to north western Europe: *

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

* In

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

occasionally also in the interior. It is introduced to

Menorca Menorca or Minorca (from la, Insula Minor, , smaller island, later ''Minorica'') is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. Its name derives from its size, contrasting it with nearby Majorca. Its capi ...

. - A subspecies, ''Theba pisana arietina'', from coastal habitats in Spain and Portugal, is on the Red List as Endangered. *

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

Malta Malta ( , , ), officially the Republic of Malta ( mt, Repubblika ta' Malta ), is an island country in the Mediterranean Sea. It consists of an archipelago, between Italy and Libya, and is often considered a part of Southern Europe. It lies ...

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

Commonwealth of Australia. (April 2002)
"Citrus Imports from the Arab Republic of Egypt. A Review Under Existing Import Conditions for Citrus from Israel"
. Agriculture, Fisheries and Forestry, Australia. Caption: Gastropods, page 12 and Appendix 2. * Belgium * central Atlantic islands The species has been introduced to numerous other areas, including: * southwestern England and south Wales,

Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...

: - introduced since at least the 1700s * eastern and southern

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

- introduced since at least the 1700s and it is still spreading along frost-free coastal localities. *

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

- non-indigenous * the United States in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

* parts of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

* southeastern Australia, southwestern Australia and

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

Clarke, G. M., Gross, S., Matthews, M., Catling, P. C., Baker, B., Hewitt, C. L., Crowther, D., & Saddler, S. R. 2000, ''Environmental Pest Species in Australia'', Australia: State of the Environment, Second Technical Paper Series (Biodiversity), Department of the Environment and Heritage, Canberra. *

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

Odendaal L. J., Haupt T. M. & Griffiths C. L. (2008). "The alien invasive land snail ''Theba pisana'' in the West Coast National Park: Is there cause for concern?". ''

Koedoe - African Protected Area Conservation and Science ''Koedoe'', subtitled ''African Protected Area Conservation and Science'', is a peer-reviewed open access scientific journal covering biology, ecology, and biodiversity conservation in Africa. It was established in 1958. Koedoe is Afrikaans for Ku ...

'' 50(1): 93-98
abstract
. - It was introduced into South Africa prior to 1881. It has invaded the

fynbos Fynbos (; meaning fine plants) is a small belt of natural shrubland or heathland vegetation located in the Western Cape and Eastern Cape provinces of South Africa. This area is predominantly coastal and mountainous, with a Mediterranean clim ...

biome in South Africa. Given the very high densities that ''Theba pisana'' can attain at some sites, plus their apparently not particular feeding habits, their potential impact on the vegetation is cause for concern and should be further investigated. In many of these places ''T. pisana'' has become a problematic

and a serious agricultural pest. This species is already established in the USA, and is considered to represent a potentially serious threat as a pest, an

which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore it has been suggested that this species be given top national

quarantine A quarantine is a restriction on the movement of people, animals and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been ...

significance in the USA. File:Theba_pisana_02.JPG, Theba pisana pisana File:Theba_pisana_01.JPG, Theba pisana pisana File:Theba_pisana_ampullacea_02.JPG, Theba pisana ampullacea File:Theba_pisana_ampullacea_01.JPG, Theba pisana ampullacea File:Theba pisana carpiensis 01.JPG, Theba pisana carpiensis File:Theba_pisana_concolor_01.JPG, Theba pisana concolor File:Theba_pisana_dermoi_01.JPG, Theba pisana dermoi File:Theba pisana fauxrosea 01.JPG, Theba pisana fauxrosea File:Theba_pisana_ferruginea_01.JPG, Theba pisana ferruginea File:Theba pisana lineolata 01.JPG, Theba pisana lineolata File:Theba_pisana_major_01.JPG, Theba pisana major File:Theba_pisana_minor_01.JPG, Theba pisana minor File:Theba_pisana_musica_01.JPG, Theba pisana musica File:Theba_pisana_semifulva_01.JPG, Theba pisana semifulva File:Theba pisana sertum 01.jpg, Theba pisana sertum

Description

The shell background color is a creamy white. Different individuals may have shells with varying degrees of pale to dark brown markings. The markings, when present, may be in the form of uninterrupted spiral bands, spiral dotted lines, or small radial smudges. The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard ou ...

can be found in various colour variants, but is basically yellow or white with dark color bands or spots and often a dark bluish grey apex. The shells of juveniles are sharply keeled, however the keel is not present on the final adult whorl. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

often has a lip that is light reddish on the inside, and the lip margin is only reflected at columellar side. The umbilicus is narrow and half covered by the reflected columellar margin. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex ...

has a characteristic size in the eastern Mediterranean when compared with other species, where there are no other ''Theba'' species. The umbilicus is also rarely seen in other species. Juveniles of ''

Eobania vermiculata ''Eobania vermiculata'' also known as ''Helix vermiculata'', common name the "chocolate-band snail" is a species of large, air-breathing, land snail, a Terrestrial animal, terrestrial pulmonate gastropod mollusk in the family Helicidae, the true ...

'' have a considerably larger apex. The width of the shell is 12–25 mm, but in Greece the adult shells are usually below 15 mm in width. The height of the shell is 9–20 mm. The visible soft parts are very light yellowish with dark colour bands running from the sides to the upper tentacles; the tentacles are very long. This snail is sometimes confused with ''

Cernuella virgata ''Cernuella virgata'', also known as ''Helicella virgata'', common name, the "vineyard snail", is a species of small, air-breathing land snail, a pulmonate gastropod mollusc in the family Geomitridae.MolluscaBase eds. (2020). MolluscaBase ...

'', a species with a much smaller and less inflated shell.

Ecology

Theba pisana on Foeniculum vulgare, Montbazin, Hérault 03

''Theba pisana'' usually lives in coastlands, in or near sandy habitats. In hot climates it

aestivate Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a ...

s often directly exposed to the sun, attached to grasses, shrubs or succulent plants, fence posts, tall weeds, and so on. It is common near beaches. In

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...

s it can live on nearly bare sand that is poorly fixed in place by grasses. In colder regions the snails do not aestivate, but they do climb on plants in dry weather. This snail does not survive serious winter frosts. ''Theba pisana'' is often associated with two other land snail species '' Cochlicella acuta'' and ''

'', but it can live slightly deeper inside pure sandy habitats, and is usually more common than ''Cochlicella acuta''. It is one of the most common snails in coastal regions from south Portugal to Greece. In South Africa, a study showed that these snails were most abundant along roadsides; densities decreased dramatically with distance from roads. The snails were observed to be living on a variety of endemic and introduced plant species; these snails appear to be able to eat an unusually wide range of different food sources. ''Theba pisana'' is also a significant pest of

citrus ''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...

vine A vine (Latin ''vīnea'' "grapevine", "vineyard", from ''vīnum'' "wine") is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas or runners. The word ''vine'' can also refer to such stems or runners themselv ...

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

crops and

cereal A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...

s in South Africa. In Australia, it feeds on a range of agricultural plants. Most ''Theba pisana'' snails have an annual life cycle, breeding in summer and autumn, but a few also take 2 years to mature. In aestivating T. pisana populations in Israel some individuals retain an immature size and shape and a rudimentary status of the genital system, defined as 'infantiles'; the populations of T. pisana may be self-regulated by the mechanism of infantilism or controlled by humidity or, perhaps, by both. In South Africa, ''Theba pisana'' appear to have an annual lifecycle, breeding in autumn to winter and growing to adult size of about 14 mm diameter by the end of the following summer. Maturity is reached at half maximum shell size after 1 year. Maximum shell size is attained after 2 years. This species of snail makes and uses

love darts A love dart (also known as a gypsobelum, shooting darts, or just as darts) 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. The ...

. The size of the egg is 2.2 mm.Heller J.: ''Life History Strategies''. in Barker G. M. (ed.):
The biology of terrestrial molluscs
'. CABI Publishing, Oxon, UK, 2001, . 1-146, cited page: 428. In South Africa, the

population density Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.Matt RosenberPopul ...

can reach up to 300-700 snails m². In South Africa, these snails are active mostly at night and especially during periods of high humidity, irrespective of temperature.

Parasites

''Theba pisana'' is an intermediate host for the terrestrial

trematode Trematoda is a class of flatworms known as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host ...

parasite ''

Brachylaima cribbi ''Brachylaima cribbi'' is a species of terrestrial trematode parasites in the family Brachylaimidae. Overview Intermediate hosts for ''Brachylaima cribbi'' are terrestrial snails '' Cochlicella acuta'', ''Cernuella virgata'' and ''Theba pisana ...

''.

Impact of invasions

In addition to the direct negative effect of ''Theba pisana'' feeding on agricultural crops, it also has several other additional effects. It uses the stalks of cereals as aestivating sites, which in turn clogs machinery and fouls produce during mechanical harvesting. According to Quick (1952) ''Theba pisana'' has been responsible for the extermination of native snail species as a result of

competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...

for available food. In their report on the status and potential impacts of alien invasive organisms in the

biome, MacDonald & Jarman (1984)MacDonald I. A. W. & Jarman M. L. (1984). "Invasive alien organisms in the terrestrial ecosystems of the fynbos biome, South Africa". ''South African National Scientific Programmes Report'' No. 85. predicted that ''Theba pisana'' would have very little impact on

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

processes, such as

nutrient cycling A nutrient cycle (or ecological recycling) is the movement and exchange of inorganic and organic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cycli ...

, energy flow and sediment dynamics or on the germination and succession processes of the plant community itself. However, the snail could seriously impact directly on fynbos plants, by feeding on them, and also displace native herbivores by competing with them for resources, and these effects have not been studied.

References

This article incorporates public domain text from the reference"Species summary for ''Theba pisana''"

AnimalBase AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and pr ...

, last modified 2 February 2011, accessed 11 May 2011. and CC-BY-3.0 text from the reference

External links

Animalbase.uni-goettingen.de: ''Theba pisana''
— ''at

Animalbase AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and pr ...

: taxonomy, short description, distribution, biology, status (threats), images''.
Encyclopedia of Life—EOL.org ''Theba pisana'' images

Pestalert.org: ''Theba pisana'' (white garden snail)

— ''

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

Institute of Food and Agricultural Sciences The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is a teaching, research and Extension scientific organization focused on agriculture and natural resources. It is a partnership of federal, state, and county governmen ...

"Featured Creatures website."''
Snailcream.in.th: White garden snail
- Images of shell variations in ''C. hortensis'' (Thai language translate). {{Taxonbar, from=Q1940276 Helicidae Molluscs of Europe Agricultural pest molluscs Gastropods described in 1774 Taxa named by Otto Friedrich Müller Gastropods of Africa