Deroceras laeve
Encyclopedia
Deroceras laeve, the marsh slug, is a species
of small air-breathing land slug
, a terrestrial
pulmonate gastropod mollusk in the family Agriolimacidae.
, from the subpolar zones to the southern margins. Today this slug species has been introduced worldwide except Antarctica, also on tropical islands such as New Guinea
and on Pacific islands.
Europe:
Asia:
The Americas:
covers 50 % of body length (unusually large). There are wrinkles on skin present (may disappear in preserved slugs). Mucus is thin, colourless.
This slug is 15–25 mm long when preserved.
The populations of this species that occur in Central Europe are much darker than other Deroceras species in that area.
Reproductive system
: Penis is often reduced, elongated if present, without proper penial gland but with two or more tiny glandular papillae and its end. Retractor is unforked and attached at half penis length, stimulator small, cone-shaped but looks more like a papilla. Tubular oviductus and atrium are unusually long. There is no rectal caecum.
. It tolerates subpolar and tropical temperatures. Newly created habitats are often colonized after a few years. In Switzerland in up to 1800 m altitude, but usually below 1000 m, in Bulgaria in up to 2500 m.
Deroceras laeve can be a serious pest in greenhouses. On the other hand the species is threatened by continuous elimination of wet habitats
by drainage
, construction projects and road construction.
It is the only land gastropod that goes deliberately into the water and can survive for days submerged. Because of this unusual behavior, the species can be dispersed by flowing water.
The life cycle is extremely short, and can take place within less than a month. This species can have up to 5 generations in a year, with several generations alive at the same time. Frequently there are forms with a reduced penis, which reproduce by self-fertilisation. The maximum age of this slug is not more than 1 year.
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 small 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 Agriolimacidae.
Distribution
The distribution of Deroceras laeve was originally PalearcticPalearctic
The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...
, from the subpolar zones to the southern margins. Today this slug species has been introduced worldwide except Antarctica, also on tropical islands such as New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
and on Pacific islands.
Europe:
- British Isles: Great Britain and Ireland. The species has shown little evidence for significant decline in Britain.
- Czech Republic - least concern (LC)
- Netherlands
- Poland
- Slovakia
- Sweden
- Switzerland - lower concern in Switzerland
- and others
Asia:
The Americas:
- California
- El Hatillo Municipality, Miranda, Venezuela
- Colombia
- introduced to Dominica (first report in 2009)
- and others
Description
The slug is from brown to dark brown, usually with dark and characteristic but not well visible spots arranged in groups. The shape is almost cylindrical, posterior end is abruptly widened. The mantleMantle (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...
covers 50 % of body length (unusually large). There are wrinkles on skin present (may disappear in preserved slugs). Mucus is thin, colourless.
This slug is 15–25 mm long when preserved.
The populations of this species that occur in Central Europe are much darker than other Deroceras species in that area.
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 often reduced, elongated if present, without proper penial gland but with two or more tiny glandular papillae and its end. Retractor is unforked and attached at half penis length, stimulator small, cone-shaped but looks more like a papilla. Tubular oviductus and atrium are unusually long. There is no rectal caecum.
Habitat
Deroceras laeve has high ecological tolerance, but needs permanently wet habitats. It is usually found in lowlands and very humid habitats, swamps, riversides, wetlands, especially alder and oak woods, marshlands and degraded areas, also greenhouses, often near water under wood or detritusDetritus
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...
. It tolerates subpolar and tropical temperatures. Newly created habitats are often colonized after a few years. In Switzerland in up to 1800 m altitude, but usually below 1000 m, in Bulgaria in up to 2500 m.
Deroceras laeve can be a serious pest in greenhouses. On the other hand the species is threatened by continuous elimination of wet habitats
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
by drainage
Drainage
Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...
, construction projects and road construction.
It is the only land gastropod that goes deliberately into the water and can survive for days submerged. Because of this unusual behavior, the species can be dispersed by flowing water.
Feeding habits
These slugs are agile and crawl quickly. They are omnivorous, but live and dead plant remains are preferred.Life cycle
The eggs of this species can also survive when submerged; juveniles can hatch underwater and then climb to the surface.The life cycle is extremely short, and can take place within less than a month. This species can have up to 5 generations in a year, with several generations alive at the same time. Frequently there are forms with a reduced penis, which reproduce by self-fertilisation. The maximum age of this slug is not more than 1 year.
External links
- Deroceras laeve on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
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