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Identification Guide
Common Name: Ashy-Grey Slug
Scientific Name: Limax cinereoniger
Body Colour: Ash-grey colour
Size: 25cm when fully grown
Habitat: Found across the UK but normally
restricted to mature and undisturbed
woodlands and is often found under logs
Extra Information: This slug has a yellow keel along its back from head to tail and is the largest
native slug in the UK. The juveniles of this species have uniformly pale undersides.
Common Name: Brown-Banded Arion
Scientific Name: Arion circumscriptus
Body Colour: Dark grey or brown
Size: It can grow up to 5cm
Habitat: Found in cool and humid forests and are
often found on fallen logs
Extra Information: The underside of this species is
whitish and its mucus is colourless. The juveniles of this species have light grey sides. This slug
feeds on humus, decaying leaf mould, and live and decaying vegetation.
Common Name: Chestnut Slug
Scientific Name: Deroceras invadens
Body Colour: Grey-brown
Size: 2-3.5 cm when mature
Habitat: Widespread across the UK and can be
found in gardens
Extra Information: This species often has a pale
ring around its respiratory pore. A good way to
identify this slug is that it is fairly fast moving
and will be the first slug to move away when disturbed.
Common Name: Common Garden Slug
Scientific Name: Arion distinctus/ Arion horntensis
Body Colour: Brown
Size: 3cm when mature
Habitat: Common in the north of England, lowlands of
Scotland and parts of Ireland and is common on
agricultural land.
Extra Information: Its underside is orange or yellow
and so is its body mucus. Also it is striped lengthwise
and covered in tiny gold spots. This species of slug attacks both leaf and root crop, and is a major
pest of potatoes.
Common Name: Common Keeled Slug
Scientific Name: Tandonia budapestensis
Body Colour: Black or grey
Size: 6cm when mature
Habitat: Remains mostly underground
Extra information: This slug has a yelloworange ridge along its body, has a pale
underside and colourless mucus. It will feed
on newly drilled seeds underground, badly affecting crops such as potatoes. As it spends most of
its time underground it is hard to control.
Common Name: Dusky Slug
Scientific Name: Arion subfuscus
Body Colour: Pale shade of brown
Size: 7cm at maturity
Habitat: Common in most parts of the UK and
are found in woodlands where it hides under
stones and dead wood, hedgerows and is also
found in gardens and allotments
Extra Information: This slug also has dark brown lengthwise strips, orange body mucus, a yellow
underside, colourless sole mucus and pale tentacles. This slug feeds mostly on fungi, decaying or
yellowed foliage, unprotected plant parts (e.g. petals) and occasionally animal faeces, dead or
injured earthworms and insect larvae.
Common Name: Grey Field Slug
Scientific Name: Deroceras reticulatum
Body Colour: Varies but is normally light brown
with a chain of darker veins and blotches
Size: Between 3cm and 5cm in length (when
extended)
Habitat: Widespread throughout the UK and is
common in gardens and on agricultural land
Extra Information: The keel of this slug is cut short at the tail and the body can look lumpy. The
mucus of this species is colourless and when disturbed mucus is produced in large quantities. Its
underside is whitish with a darker zone along the centre. This species of slug feeds most
commonly on seeds and plants above ground and is a major threat to cereal crops.
Common Name: Large Red Slug and Black Slug
Scientific Name: Arion rufus/ater
Body Colour: Either orange-red or black. The most common
colour is black with an orange fringe.
Size: It can reach up to 12cm in length
Habitat: Common throughout the UK in most terrestrial habitats such as peat land, farmland and
hedgerows.
Extra Information: When this slug is alarmed it contracts into a spherical shape and might rock
from side to side. Its mucus is colourless and this species of slug will sometimes eat seedlings on
agricultural land.
Common Name: Lemon Slug
Scientific Name: Limax tenellus
Body Colour: Bright Yellow
Size: Maximum length is 4cm
Habitat: Occurs throughout the UK
although it is highly localised. This
slug species is almost always found in
woodland
Extra Information: This species of slug feeds on fungi and is a very low risk to agricultural crops. It
has dark tentacles and a small keel at the end of its body. It is also a good indicator of ancient
sites.
Common Name: Leopard Slug
Scientific Name: Limax maximus
Body Colour: Brown or grey with brown or black
spots/blotches. The colouration of both juveniles
and adults is similar.
Size: It can grow up to 16cm in length
Habitat: This slug species is widespread and
common in the UK and they favour woodland and
old gardens with mature trees.
Extra Information: The underside of the slug is
white and it has an obvious keel along the rear of its
body. Its mucus is sticky and this species is a low risk to agricultural crops. Leopard slugs don’t
damage living plants, but eat other slugs including species that can damage garden plants and
vegetables. They also eat dead and rotting plants along with fungi and this recycles nutrients and
fertilises soil. The Leopard slug can be easily confused with other juvenile slugs, due to its
markings; however juveniles will be less than 7cm in length.
Common Name: Orange-Banded Arion
Scientific Name: Arion fasciatus
Body Colour: Yellowish grey or brown
Size: It can grow up to 5cm or even 7cm in
length
Habitat: Mainly lives in open habitats and can
be found in shady places below trees and bushes
in herbs and in leaf litter.
Extra Information: The underside of this species
is yellowish and it may have a slight keel. The
juveniles are light greyish brown and have darker bands.
Common Name: Silver slug
Scientific Name: Arion silvaticus
Body Colour: Grey-Brown with dark coloured longitudinal
stripes
Size: It can grow to 3-4cm
Habitat: Fairly frequent and widespread in the UK, this
species is often found under leaf litter, in acid woodland,
heath land, sea cliffs and mountains.
Extra Information: The underside of this species is whitish or
cream coloured, its mucus is clear or light yellow and the
head and tentacles are black. The juveniles of this species
are light bluish grey with blurred darker bands and a whitish
keel line.
Common Name: Shelled Slug
Scientific Name: Testacella scutulum
Body Colour: Pale orange
Size: 10cm in length when mature
Habitat: It spends most of its life under
the soil surface
Extra Information: This is an
extraordinary slug as it has a small finger- like shell of about 7-8mm long, covering its rear end. It
has a yellowish or whitish underside and it is a predator of earthworms so is unwelcome on
agricultural land.
Common Name: Hedgehog Arion
Scientific Name: Arion intermedius
Body Colour: Creamy white, bluish yellow, olive or brown
Size: It can grow to between 2.5cm and 3.5cm
Habitat: This species lives in the leaf litter zone of humid
deciduous forests and in areas near to water.
Extra Information: The tentacles of this species are small
and darkly coloured and its mucus is light yellow and it is
known to eat mushrooms. The name hedgehog arion
comes from the spiky warts that the slug displays when it
is contracted.
Common Name: Tree Slug
Scientific Name: Limax marginatus
Body Colour: Pale grey
Size: It can grow up to 7cm in length
Habitat: Is abundant on trees in woodland, hedgerows,
walls and natural rocks.
Extra Information: This species of slug is marked by two
dark lines on both sides of the body and has a greyishwhite underside. Also the mucus of this species is colourless and watery and large amounts of this
are produced especially when it is disturbed.
Common Name: Yellow Slug
Scientific Name: Limax flavus
Body Colour: Marbled and mottled olive colour.
The colouration of both juveniles and adults is
similar.
Size: It can grow up to 10cm in length
Habitat: Most common and widespread in
England, Wales and Ireland and are mostly
associated with houses and gardens. They even
sometimes venture into people’s homes, especially cellars after dark.
Extra Information: This species of slug has blue tentacles and has a distinct yellow keel. It can
cause major damage to agricultural land if present as it feeds on seedlings and vegetables.
Invasive Species:
Common Name: Spanish Slug
Scientific Name: Arion vulgaris
Body Colour: Red-Brown
Size: 8cm-15cm when mature
Habitat: This is a non native species of slug
and it is now known to be an established
species in the UK.
Extra Information: These slugs have an
extensive omnivorous diet that includes
excrement, dead animals and a variety of crops that are not normally susceptible to slug feeding.
They also produce twice as many eggs as slugs native to the UK and are able to tolerate hotter
and dryer environments having adapted to living in the Mediterranean. They are also known to
push out other slug and snail species to dominate an area due to their large size and high
population density.
Common Name: Spanish Stealth slug
Scientific Name: Arion Flagellus
Body Colour: Brown-Red
Size: It can grow up to 10cm in length
Habitat: First identified in the UK in 19451946 and is now widespread across the UK
and is found in a great variety of habitats
from upland acidic grassland, to lowland alder
carr and now widely in gardens.
Extra Information: This species has pale mucus
which may be tinged yellow or green, and its
underside is always pale but often tinged
green. The young have a distinctive orange-yellow colour but with broad, dark lateral bands.