Boettgerilla pallens
Encyclopedia
Boettgerilla pallens, common name
the worm slug, is a European species
of air-breathing land slug
, a terrestrial
pulmonate gastropod mollusk in the family Boettgerillidae.
in Abkhazia.
The native distribution of Boettgerilla pallens is believed to be the SW flank of the Caucasus
:
But the species has spread spectacularly over the last half century. Dates of first recorded occurrences in various countries are listed in.
In Europe, Boettgerilla pallens was first found in 1949 (in Germany). It has now been become naturalized widely in Central Europe
, Northern Europe
and Western Europe
and Eastern Europe
including:
Outside Europe it is also known, presumed as an introduction, from:
Boettgerilla pallens is very narrow and slender slug, almost worm-like and sharply keeled. The color is pale greyish or with bluish hue. The head and keel is slightly darker. The mantle
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
: Penis is elongate and broader than vagina, epiphallus and spermatheca. 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
. 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 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
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 (earthworm faeces, detritus
etc., also arionid eggs) and move on. It has been considered as a pest in European greenhouses and gardens, because slugs feed on soft plant tissues.
Mating and egg-laying is during late summer and into autumn in Britain (October in Germany). Eggs are laid as several 1-6 egg clutches 9–27 cm deep below the surface. 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.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
the worm slug, is a European species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of air-breathing land slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
, a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
pulmonate gastropod mollusk in the family Boettgerillidae.
Distribution
The type locality of Boettgerilla pallens is GudautaGudauta
Gudauta is a town in Abkhazia and a centre of the eponymous district. It is situated on the Black Sea, 37 km northwest to Sukhumi, the capital of Abkhazia....
in Abkhazia.
The native distribution of Boettgerilla pallens is believed to be the SW flank of the Caucasus
Caucasus
The Caucasus, also Caucas or Caucasia , is a geopolitical region at the border of Europe and Asia, and situated between the Black and the Caspian sea...
:
- Abkhazia
- western Georgia
But the species has spread spectacularly over the last half century. Dates of first recorded occurrences in various countries are listed in.
In Europe, Boettgerilla pallens was first found in 1949 (in Germany). It has now been become naturalized widely in Central Europe
Central Europe
Central Europe or alternatively Middle Europe is a region of the European continent lying between the variously defined areas of Eastern and Western Europe...
, Northern Europe
Northern Europe
Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...
and Western Europe
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...
and Eastern Europe
Eastern Europe
Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"...
including:
- Ireland - since 1973
- Great Britain - since 1972
- France
- Belgium
- Netherlands
- Germany
- Switzerland.
- Austria
- Czech Republic
- Slovakia
- Poland - since 1956, mainly in the south-western Poland
- Finland
- Sweden
- Lithuania
- Moscow, St. Petersburg and other cities in Russia
- Romania
- Kiev, Ukraine
- and several other countries, but conspicuously not from several southern European ones.
Outside Europe it is also known, presumed as an introduction, from:
- Tajikistan
- Turkey
- British Columbia, Canada
- Colombia
Description
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
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
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
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
Reproductive system of gastropods
The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals...
: Penis is elongate and broader than vagina, epiphallus and spermatheca. 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
Milax gagates, common name the "greenhouse slug" is a species of air-breathing, keeled, land slug, a shell-less terrestrial gastropod mollusk in the family Milacidae.-Description:...
. 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.
Ecology
Reise et al. (2000) review aspects of the species 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
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...
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 (earthworm faeces, detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
etc., also arionid eggs) and move on. It has been considered as a pest in European greenhouses and gardens, because slugs feed on soft plant tissues.
Mating and egg-laying is during late summer and into autumn in Britain (October in Germany). Eggs are laid as several 1-6 egg clutches 9–27 cm deep below the surface. 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.