Milax gagates
Encyclopedia
Milax gagates, common name
the "greenhouse slug" is a species
of air-breathing, keel
ed, land slug
, a shell-less terrestrial
gastropod mollusk in the family Milacidae
.
is relatively large (35-40 % of body length), with distinct grooves. The keel is prominent between mantle and posterior end. Skin sculpture is weak. There are 16-17 grooves between keel and pneumostome
. The sole of the foot has blackish lateral zones and a lighter medial zone.
Milax gagates is up to 50 mm long. Preserved specimen have a length of 25-30 mm and a width of 6-8 mm. The weight of adult slugs ranges from 991.2 mg to 3308.0 mg.
Reproductive system
: The penis is rounded, and half as long as the epiphallus. The epiphallus is slightly widened and truncated (as if cut off) at its end. the vas deferens is short (usually not longer than epiphallus), opens asymmetrically at the truncated end of the epiphallus. The atrium is short, and not widened. The accessory gland consist of several elongate glands and is connected to the atrium by some 20 short coiled tubular ducts. The stimulator is narrow, conical, slightly flattened at its end with some papillae.
The stimulator of the similar species Milax nigricans has more papillae situated at its base and not near its free end.
It is Endangered in Rhineland-Palatinate
, Germany.
The species may be native to the Canary Islands.
Milax gagates has been introduced in the area between Portugal and Galicia, the Atlantic coastlands of France to Belgium, the British Isles, and in many other areas almost worldwide (Australia, Tasmania, New Zealand, Japan, Pacific islands, South Africa, Atlantic islands). As an introduced species it now occurs in a number of countries and islands including:
It feeds on fresh herbs, including the roots, it can sometimes be noxious to crops (carrots, potatoes). It is occasionally (in areas of western Britain) damaging to gardens and crops. It is an agriculture pest on soybean
, sunflower
and oilseed rape in Argentina.
In Britain copulation takes place during the period from spring to autumn. During copulation both slugs cling together so closely that no everted genitalia are visible. Under laboratory conditions, the first eggs are laid 5-15 days after copulation. At one time approximately 15 eggs are laid. This can be repeated several times, but in total not more than 100 eggs are laid by one individual. The dimensions of the eggs are 2 × 1.5 mm. Self-fertilization is also possible.
15-30 days after egg-laying, the slugs die (semelparous species). Juveniles hatch after at least 25-30 days. Maturity is reached after 4-5 months under laboratory conditions.
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 "greenhouse slug" is a 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, keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
ed, 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 shell-less 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...
gastropod mollusk in the family Milacidae
Milacidae
Milacidae is a family of air-breathing, keeled, land slugs. These are shell-less terrestrial gastropod mollusks in the superfamily Parmacelloidea.This family has no subfamilies ....
.
Description
The body of Milax gagates is an even dark grey to black, although it has somewhat lighter sides. There are no pigment spots. 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...
is relatively large (35-40 % of body length), with distinct grooves. The keel is prominent between mantle and posterior end. Skin sculpture is weak. There are 16-17 grooves between keel and pneumostome
Pneumostome
The pneumostome is a feature of the external body anatomy of an air-breathing land slug or land snail. It is a part of the respiratory system of gastropods....
. The sole of the foot has blackish lateral zones and a lighter medial zone.
Milax gagates is up to 50 mm long. Preserved specimen have a length of 25-30 mm and a width of 6-8 mm. The weight of adult slugs ranges from 991.2 mg to 3308.0 mg.
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...
: The penis is rounded, and half as long as the epiphallus. The epiphallus is slightly widened and truncated (as if cut off) at its end. the vas deferens is short (usually not longer than epiphallus), opens asymmetrically at the truncated end of the epiphallus. The atrium is short, and not widened. The accessory gland consist of several elongate glands and is connected to the atrium by some 20 short coiled tubular ducts. The stimulator is narrow, conical, slightly flattened at its end with some papillae.
The stimulator of the similar species Milax nigricans has more papillae situated at its base and not near its free end.
Distribution
The native range of Milax gagates was originally from Morocco through Tunisia and southern Spain to southern France and the Balearic Islands.It is Endangered in Rhineland-Palatinate
Rhineland-Palatinate
Rhineland-Palatinate is one of the 16 states of the Federal Republic of Germany. It has an area of and about four million inhabitants. The capital is Mainz. English speakers also commonly refer to the state by its German name, Rheinland-Pfalz ....
, Germany.
The species may be native to the Canary Islands.
Milax gagates has been introduced in the area between Portugal and Galicia, the Atlantic coastlands of France to Belgium, the British Isles, and in many other areas almost worldwide (Australia, Tasmania, New Zealand, Japan, Pacific islands, South Africa, Atlantic islands). As an introduced species it now occurs in a number of countries and islands including:
- Portugal
- Belgium
- British Isles: Great Britain and Ireland. In Britain is always local except in CornwallCornwallCornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
. - Australia and Tasmania
- New Zealand
- Japan
- Pacific islands
- South Africa
- Atlantic Islands
- United States - widely distributed. In Florida only in ports.
- Argentina
Ecology
Milax gagates lives mostly in cultivated areas, often the coast, and also in forests, shrublands, and natural meadows. It prefer habitats close to water. It hides under stones, moist ground litter and in soil cavities.It feeds on fresh herbs, including the roots, it can sometimes be noxious to crops (carrots, potatoes). It is occasionally (in areas of western Britain) damaging to gardens and crops. It is an agriculture pest on soybean
Soybean
The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...
, sunflower
Sunflower
Sunflower is an annual plant native to the Americas. It possesses a large inflorescence . The sunflower got its name from its huge, fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads...
and oilseed rape in Argentina.
In Britain copulation takes place during the period from spring to autumn. During copulation both slugs cling together so closely that no everted genitalia are visible. Under laboratory conditions, the first eggs are laid 5-15 days after copulation. At one time approximately 15 eggs are laid. This can be repeated several times, but in total not more than 100 eggs are laid by one individual. The dimensions of the eggs are 2 × 1.5 mm. Self-fertilization is also possible.
15-30 days after egg-laying, the slugs die (semelparous species). Juveniles hatch after at least 25-30 days. Maturity is reached after 4-5 months under laboratory conditions.