''Boettgerilla pallens'',

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 ...

the worm slug, is a European

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of air-breathing land

slug Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...

, a terrestrial

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

Boettgerillidae ''Boettgerilla'' is a genus of air-breathing land slugs, terrestrial pulmonate gastropod molluscs in the family Boettgerillidae. The generic name ''Boettgerilla'' is named after the German malacologist Oskar Boettger. Taxonomy ''Boettger ...

Distribution

The type locality of ''Boettgerilla pallens'' is Gudauta in

Abkhazia Abkhazia, ka, აფხაზეთი, tr, , xmf, აბჟუა, abzhua, or ( or ), officially the Republic of Abkhazia, is a partially recognised state in the South Caucasus, recognised by most countries as part of Georgia, which vi ...

.Kantor Yu I., Vinarski M. V., Schileyko A. A. & Sysoev A. V.(published online on December 22, 2009). "Catalogue of the continental mollusks of Russia and adjacent territories"
Version 2.3.
/ref> The native distribution of ''Boettgerilla pallens'' is believed to be the SW flank of the

Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range, have historically ...

: *

* western Georgia Maybe it is also native to Armenia, the

Crimean Mountains The Crimean Mountains ( uk, Кримські гори, translit. ''Krymski hory''; russian: Крымские горы, translit. ''Krymskie gory''; crh, Qırım dağları) are a range of mountains running parallel to the south-eastern coast o ...

and Donetsk Upland in

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

.Balashov I.A. & Baidashnikov A.A. 201
The first findings of a slug ''Boettgerilla pallens'' (Stylommatophora, Boettgerillidae) in Crimea''
Ruthenica. 22(2): 111-114. But the species has spread spectacularly over the last half century. Dates of first recorded occurrences in various countries are listed in Reise et al. (2000). In Europe, ''Boettgerilla pallens'' was first found in 1949 (in Germany). It has now become naturalized in most of Europe although it has conspicuously not been reported from most of Spain, Italy and the Balkan Peninsula. Countries where it occurs include: *

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 ...

- since 1973 *

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 ...

- since 1972 *

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

* Belgium *

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 ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

. *

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

Slovakia Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the s ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...

- since 1954, mainly in the south-western Poland *

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

Lithuania Lithuania (; lt, Lietuva ), officially the Republic of Lithuania ( lt, Lietuvos Respublika, links=no ), is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea. Lithuania ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

: Moscow, Saint Petersburg and other cities * Spain (north only) and Andorra * Italy (north only) * Romania * Bulgaria *

Kyiv Kyiv, also spelled Kiev, is the capital and most populous city of Ukraine. It is in north-central Ukraine along the Dnieper, Dnieper River. As of 1 January 2021, its population was 2,962,180, making Kyiv the List of European cities by populat ...

Lviv Lviv ( uk, Львів) is the largest city in western Ukraine, and the seventh-largest in Ukraine, with a population of . It serves as the administrative centre of Lviv Oblast and Lviv Raion, and is one of the main cultural centres of Ukraine ...

Ivano-Frankivsk Ivano-Frankivsk ( uk, Іва́но-Франкі́вськ, translit=Iváno-Frankívśk ), formerly Stanyslaviv ( pl, Stanisławów ; german: Stanislau), is a city located in Western Ukraine. It is the administrative centre of Ivano-Frankivsk O ...

Vinnytsia Vinnytsia ( ; uk, Вінниця, ; yi, װיניצע) is a city in west-central Ukraine, located on the banks of the Southern Bug. It is the administrative center of Vinnytsia Oblast and the largest city in the historic region of Podillia. A ...

, some cities of

Crimea Crimea, crh, Къырым, Qırım, grc, Κιμμερία / Ταυρική, translit=Kimmería / Taurikḗ ( ) is a peninsula in Ukraine, on the northern coast of the Black Sea, that has been occupied by Russia since 2014. It has a pop ...

and others * Iceland Outside Europe it is also known, presumed as an introduction, from: * Western Siberia (Russia) *

Tajikistan Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...

* Turkey * Canary Islands (Spain) * Canada: British Columbia, Newfoundland, Quebec * USA: California, Oregon * Mexico *

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

Description

''Boettgerilla pallens'' is very narrow and slender slug, almost worm-like and sharply

keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...

ed. The color is pale greyish or with bluish hue. The head and keel is slightly darker. The

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

is pointed at its posterior end and equipped with fine concentrical grooves. Sole is pale yellow. Mucus is colourless. Juveniles are yellowish to dirty white. The body length is up to 60 mm. The width is up to 3 mm. The shell is small, fragile, 1.5–3 x 0.8–1.5 mm, with median nucleus and growth lines, denser in the posterior part, no thin margin, located below the very terminal section of the pointed end of the mantle.

Reproductive system The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are als ...

: Penis is elongate and broader than vagina, epiphallus and

spermatheca The spermatheca (pronounced plural: spermathecae ), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other ...

. Epiphallus is swollen and connected to penis laterally near its posterior end, by a long thin duct, which is thinner than vas deferens. Vagina as long as penis and almost as narrow as vas deferens. There are no accessory glands. The spermatheca is elongate and relatively short. ''Boettgerilla pallens'' is much more slender than ''

Milax gagates ''Milax gagates'', known by the common name greenhouse slug, is a species of air-breathing, keel (slug), keeled, land slug, a shell-less terrestrial molluscs, terrestrial gastropod mollusc in the family Milacidae.Marshall, B. (2014). Milax gagate ...

''. The sole is more slender. In ''Milax gagates'' the posterior end of the mantle is rounded, its shell is larger and better visible, its colour more yellowish-brownish. Boettgerilla pallens 3

Ecology

Reise et al. (2000) review aspects of the distribution, mode of range expansion, and other aspects of its ecology. ''Boettgerilla pallens'' inhabits a very wide range of habitats, including gardens, grassland, coniferous and deciduous woodland, and is tolerant of a wide range of soil pH, calcium content and water content. It lives at altitudes of up to 1750 m in the Caucasus and in Switzerland at up to 1600 m, but usually below 700 m. It can be considered as synanthropic, although it is now often found also in undisturbed habitats. Although it may often been found under logs and stones, it is predominantly subterranean, adapted to moving through

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...

burrows and similar spaces in soil, 2–20 cm (maximum up to 60 cm) below surface. Snails move rapidly away from bright light sources. Feeding is seldom intensive: slugs usually take a few bites (of earthworm faeces,

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

etc., also arionid eggs) and move on. Although often found in gardens and greenhouses, it has only rarely been considered a pest. One study reports it coming to the surface at night to predate snails. Mating and egg-laying is during late summer and into autumn in Britain (October in Germany). Eggs are laid 9–27 cm below the surface as several clutches of 1–6 eggs . Adults survive egg-laying but die shortly afterwards. Juveniles hatch after 20–22 days at 17 °C (in Germany), between October and December (in Britain). Juveniles turn colour from white to grey in May–June.

References

This article incorporates public domain text from the reference."Species summary for ''Boettgerilla pallens''"
. AnimalBase, last modified 28 December 2008, accessed 8 September 2010.

Distribution

Description

Ecology

References

Further reading