Slugs of Britain & Ireland

TEST VERSION 2013

SLUGS OF BRITAIN & IRELAND (Short test version, pages 18-37 only)

By Ben Rowson, James Turner, Roy Anderson & Bill Symondson

PRODUCED BY FSC 2013. TEXT AND PHOTOS © NATIONAL MUSEUM OF WALES 2013 External features of slugs

Tail Mantle Head

Keel Tubercles

Lateral bands Genital pore Identification of Slugs Identification Tentacles. Breathing pore (pneumostome)

Keel Eyes

Variations in lateral banding Mantle markings and ridges

Broken lateral bands Mouth

Solid lateral bands Sole (underside of foot)

Mantle. Note texture and presence of grooves and ridges, as Tubercles. Note whether numerous and small/fine vs. few and well as any markings and banding. large/coarse. Pigment may be present in the grooves between tubercles. Tentacles. Note colour. Slugs may need to be handled or disturbed to extend tentacles. Keel (raised ridge). Note length and whether truncated at the tip of tail. Beware markings that may exaggerate or obscure the Breathing pore (pneumostome). length of keel. On right-hand side of body. Note whether rim is noticeably paler or darker than body sides. Sole (underside of foot). Note colour and any patterning. The sole in most slugs is tripartite i.e. there are three fields running Lateral bands. Note whether present on mantle and/or tail. in parallel the length of the animal. Is the central field a different Note also intensity, whether broad or narrow, and whether high shade from the lateral fields or low on body side.

Shell

Dorsal grooves. In Testacellidae, note wheth- Mucus pore. er the two grooves meet in front of the shell or Present only in Arionidae underneath it.

Foot fringe. In Arionidae, note fringe colour and if Mantle. In Testacellidae and Trigonochlamydidae, stripes are present or not. the mantle is situated near the tail but may be con- cealed by the shell, if present.

18 Identifying slugs Using the identification charts

Living, adult slugs are the easiest to identify. Live slugs This book contains both identification charts and species differ in the shapes they adopt when contracted, accounts. [Not in test version.] We recommend that and their behaviour when disturbed. They may need inexperienced users first try the charts for identification. to be examined closely, especially if small (a lens is They draw attention to important features and away recommended). White tissue or paper is useful to check from distracting ones. The charts are designed to work the colour of the mucus. Always wash your hands after without the species accounts, although these should be handling slugs. Many species can be identified from consulted for additional features and useful background good photographs provided these show enough of the information to confirm identifications. key features. The right-hand side of the body contains more features since this is where the genital pore and Most of the charts offer several identification options at breathing pore are situated. Dead slugs (e.g. from beer once. Species (or groups of species) and identification or pitfall traps) may become difficult to identify as shapes features are arranged in vertical columns or horizontal distort and colours fade. Some species have to be killed rows. The rows sometimes run across two pages. Where and dissected for accurate identification (see p. 000) in a feature is shared by more than one species (or group of which case any observations or photographs of the live species) the box is spread across columns or rows. animal need to be taken first! It is important to examine several features in turn, There are two main problems with slug identification. ruling out as many species as possible each time. Boxes Firstly, many species are extremely variable in with a red outline highlight particularly distinctive appearance. In particular, size, colour and markings can features that will often work as shortcuts to the right vary between localities and habitats and even among identification. slugs from a single clutch of eggs. They often change radically as slugs grow. Only one or a few species will correspond with all features, except in cases of exceptional variability. If the slug Secondly, juveniles of some species may resemble the being identified does not correspond with all features, adults of others. Some species have a loosely-defined try returning to an earlier chart to check it is in the right adult season, but juveniles can be encountered at any group of species. Other species may be found in Britain time of year. Without experience there is no easy way to and Ireland in future, but the vast majority of slugs will distinguish a juvenile of a large species from an adult of belong to the known species. a small species. Most slugs of 50 mm or more long will be mature enough to identify, but some species become Some externally similar slug species cannot be adult at just 15 mm. Of course, slugs encountered mating distinguished without dissection. Such cases are or laying eggs will be adult. In some species the genital indicated in the charts. pore also becomes subtly swollen in adults. Juveniles may have noticeably bigger optic tentacles, relative to For encouragement, remember that: their body size.

These problems make it difficult to construct and use a •• Not every single slug you find will be identifiable, dichotomous key (a key that presents only two options at least at first. Juveniles especially are often not at a time). We have therefore adopted charts or tabular distinctive enough to identify to species. keys that show several options at once. Where possible, the identification charts emphasize shape, texture and •• With practice, especially as one encounters more behavioural features over size, colour, and markings. species, identification becomes easier. This is They are designed to work for both adults and (as far as motivation to keep exploring! possible) juveniles.

0 mm 50 mm 100 mm 150 mm 10 20 30 40 60 70 80 90 110 120 130 140 [ Very small ][ Small ][ Medium-sized ][ Large ][ Very large Identification of Slugs Identification (Approx. max recorded size 200 mm) 19 1. Major Groups I

1a. External shell Group

Shell spiral and obvious, even if thin and transparent. Snails For identification, see the AIDGAP guide by Animal able to retract fully into shell. Cameron (2008).

Mantle virtually hidden within shell. Identification of Slugs Identification

Shell a loosely coiled spiral, very thin, transparent. Semi-slugs (Vitrinidae) Animal snail-like, but unable to retract fully into shell. Go to Chart 15. Mantle mainly hidden within shell, but with mantle lobes overlapping shell edge.

Shell virtually uncoiled, flattened and fingernail- Shelled Slugs (Testacellidae) like, covering only part of the rear end of the animal. Go to Chart 14. Mantle virtually hidden beneath shell.

Other Slugs No visible external shell. Go to 1b.

1b. Mantle Position Group

Ghost Slug (Trigonochlamydidae) p. XX Mantle tiny, disc-shaped, at the very rear of the animal. Note: in extremely rare cases, Testacellidae (p.xx) have been found alive but lacking a shell

Mantle cloak-like or shield-like, covering the neck Other slugs and “shoulders” of the animal. Mantle is of a very different texture from rest of body with breathing Go to Chart 2. pore on right side.

20 2. Major Groups II

Round-backed Slugs Long-keeled Slugs Short-keeled Slugs Short-keeled Slugs 2. (Arionidae) (Milacidae, Boettgerillidae) (Limacidae) (Agriolimacidae)

(raised ridge) (raised No keel. Keel long, running all the way to Keel short, petering out well before the rear mantle edge. Animal round-backed. the rear mantle edge. Keel Note: a very weak keel is present in some species , especially when young, but unlike other keeled slugs these have a mucus pore at the tail tip. Tail tip Tail

Rounded, with a mucus pore Pointed, with no mucus pore. Pointed, with no mucus pore. Pointed, with no mucus pore. visible. Keel sloping sharply to tail tip. Keel sloping gradually to tail tip. Keel sloping sharply to tail tip.

groove

groove Mantle texture Mantle Mantle finely granular Mantle texture variable. A Mantle with fine concentric Mantle with fine concentric (“shagreened”). deep shaped groove is ridges, like a fingerprint. Ridges ridges, like a fingerprint. Ridges usually present, but often centred around the midpoint of centred around the breathing inconspicuous. the back. pore.

Breathing pore in front half of Breathing pore in rear half of Breathing pore in rear half of Breathing pore in rear half of mantle. mantle. mantle. mantle. Breathing pore Breathing

15 - 140 mm. 25 - 75 mm. 35 - 200 mm. 15 -50 mm

Usually rather sluggish and less Particularly poor climbers, Rather active when handled. Especially active, extending willing to extend when handled. usually found on or in the Mucus may be thin and runny. readily in the hand. Mucus may Mucus may be very sticky and ground. Strong climbers, often found be thin and milky. staining. Poor climbers. well off the ground. Adult size & behaviour size Adult

Round-backed Slugs Long-keeled Slugs Short-keeled Slugs Short-keeled Slugs (Arionidae) (Milacidae, Boettgerillidae) (Limacidae) (Agriolimacidae)

Go to Chart 3. Go to Chart 8. Go to Chart 9. Go to Chart 13. Families Identification of Slugs Identification

21 3. Arionidae: Genara & Subgenera

3. Geomalacus Arion (Kobeltia) Arion (Carinarion) Arion (Mesarion) Arion (Arion)

Medium-sized to Medium-sized Very small to small Small Medium-sized very large (60 - 90 mm). (15 - 45 mm). (30 - 45 mm). (50 - 70 mm). (60 - 140 mm). Adult size Adult Identification of Slugs Identification Tubercles Small/fine; even more Varying between species. Small/fine; central row Small/fine, even more Large/coarse; slugs so than in many smaller May appear prickly when often paler, giving the so than in many smaller nearly always rough or species. retracted. impression of of a keel i.e. species. warty to the naked eye. a “false keel”.

A ball, formed by Varies from a dome to A flattened dome, bell- An elongate dome, very A near- hemispherical Retracted shape bending the sole in half. elongate; less flattened shaped in cross-section. seldom hemispherical. dome. than in subgenus May squirm or rock from Carinarion. side to side if disturbed.

Colourless. Mucus yellow-orange, at Colourless. Mucus yellow-orange, Mucus thick, sticky and Mucus least on the sole, staining staining fingers or paper. very hard to remove, fingers or paper. usually colourless.

Sole coloured Sole pale grey to Sole pale grey to yellow-orange. white, never dark. white, never dark

Back covered with pale Foot fringe broadly and spots. clearly striped from front

Other features to rear. W & SW Ireland only. Foot fringe usually Foot fringe usually Foot fringe with narrow without stripes. without stripes. stripes from front to rear.

Geomalacus Arion (Kobeltia) Arion (Carinarion) Arion (Mesarion) Arion (Arion) Genus (subgenus) p. XX Go to Chart 4. Go to Chart 5. Go to Chart 6. Go to Chart 7.

22 4. Arionidae: Arion (Kobeltia)

A. (Kobeltia) A. (Kobeltia) A. (Kobeltia) 4. A. (Kobeltia) occultus A. (Kobeltia) owenii intermedius distinctus hortensis

Very small Small Small Small Small (15 - 20 mm). (35 - 40 mm). (25 - 40 mm). (25 - 40 mm). (25 - 40 mm). Adult size Adult

(contracted) Dome-shaped A flattened dome, not Flattened, often slightly elongated. elongated. May form a ( or C shape. Body

Coarse, sometimes drawn Coarse, giving a rough or warty appearance, especially Tubercles fine, not giving Tubercles fine, not giving to slight points giving a in drier conditions. a warty appearance. a warty appearance. Tubercles “prickly” appearance in Bottom row of tubercles dry or cold conditions. often contrastingly white.

More variable than other Yellow-brown, yellow- Tawny yellow-brown to Dark grey-brown, suffused Dark blue-grey to black, Kobeltia: white to orange grey, or pale blue-grey. rich warm brown. with a trace of yellow or with little or no trace or blue-grey. Often a dull putty- coloured pigment of yellow. Often bluish Usually with obvious yellow-brown with darker on back. Never blue-grey. when young. Body colour & markingsBody colour diffuse dark pigment head. along centre of back.

Often absent; if present, High on body, not High on body, usually Low on body sides, Low on body sides, faint and high on body. diffusing gradually down diffusing down to the almost reaching foot almost reaching foot Lateral bands Lateral to foot fringe. foot fringe. fringe. fringe. Tentacles Variable., seldom black. Black to cold blue-black. Black to purplish-brown. Black to cold blue-black. Black to warm red-black.

Sole mucus: Sole mucus: Sole mucus: Sole mucus: Sole mucus:

Season: Season: Season: Season: Season: Adults all year round. Adults mainly in spring. Adults mainly in summer. Adults mainly in spring Adults mainly in autumn and summer. and winter, later than A. Other features distinctus. A. (Kobeltia) occultus A. (Kobeltia) intermedius A. (Kobeltia) sp. A. (Kobeltia) owenii A. (Kobeltia) distinctus A. (Kobeltia) hortensis (Dissection required) Species

p. XX p. XX & p. XX p. XX p. XX p. XX of Slugs Identification

23 5. Arionidae: Arion (Carinarion)

5. A. (Carinarion) fasciatus A. (Carinarion) circumscriptus A. (Carinarion) silvaticus

Small Small Small (35 - 45 mm). (30 - 40 mm). (30 - 40 mm). Adult size Adult Identification of Slugs Identification

Grey to yellow-brown. Grey to blue-grey. Grey to blue-grey, or brown. Body colour Sides & sole colour

Usually with an orange or yellow pigment No orange or yellow pigment flush along No orange or yellow pigment flush along flush along sides below lateral band. sides. sides.

Sides and sole a pale version of body colour. Sides and sole very pale, often bright white. Sides and sole very pale, often bright white. Lateral bands Lateral Relatively broad. Relatively narrow. Relatively broad.

Mantle markingsMantle No dark flecks on mantle. Dark flecks or blotches usually present on Central area of mantle may be dark, but any mantle. pigment is diffuse, not in flecks.

Mainly in disturbed habitats including farms Mainly in woods; does not extend as far Mainly open habitats (but also in woods); and some woods. into uplands and acidic habitats as A. (C.) extends further into uplands and acidic silvaticus. habitats than A. (C.) circumscriptus. Much less common in southern Britain and in Ireland than the other two species. Common throughout Britain; in Ireland, Common throughout Britain and Ireland,

Other features mainly eastern. except in eastern England.

A. (Carinarion) fasciatus A. (Carinarion) circumscriptus A. (Carinarion) silvaticus Species p. XX p. XX p. XX

24 6. Arionidae: Arion (Mesarion)

6. A. (Mesarion) iratii A. (Mesarion) fuscus A. (Mesarion) subfuscus

Medium-sized Medium-sized Medium-sized (50 - 70 mm). (50 - 70 mm). (50 - 70 mm). Adult size Adult

Pale orange-brown to dark grey. Pale orange-brown. Variable, even within populations: from bright orange-yellow, through brown and Body colour grey to (in uplands) purple-black.

Dark lateral bands present, with black spots Dark smudge present on “cheeks” below Dark lateral bands nearly always present, or speckles usually present on back. mantle edges. though may be faint, or obscured in dark Body markings individuals. Paler bands may occur above Dark lateral bands present, with a paler band the dark bands. above.

Orange or yellow. Orange, yellow, or colourless. Orange or yellow. Body Mucus

Known from upland woodlands, mainly Known from woodlands in the Cairngorms In almost all habitats, including woodlands larch plantations, in South Wales. and Sherwood Forest area; also from near and gardens. Cannock Chase and Thetford Forest. Common throughout Britain and Ireland, Records from Ireland require confirmation. except East Anglia. Other features

A. (Mesarion) cf. iratii A. (Mesarion) fuscus A. (Mesarion) subfuscus Species

p. XX p. XX p. XX Identification of Slugs Identification

25 7. Arionidae: Arion (Arion)

7. Adult size Body colour Tubercles Body markings Foot fringe colour Sole colour Other features Species

A. (Arion) flagellus Sometimes appears more flattened than other species. Medium-sized to large Often with an olive or green tint, Does not squirm

Identification of Slugs Identification (60 - 100 mm). a colour very rarely seen in other from side to side species. However, can vary from Tubercles fewer in number and Unbroken lateral bands conspicuous Usually same as body sides, Always as pale or paler than body when retracted and yellow to red to brown to grey to disturbed.

A. (Arion) flagellus A. (Arion) very coarse relative to size. in juveniles, with area between or a dirty orange. sides, and often with an olive or black, even within a population. lighter and more warmly coloured. green tinge, a colour very rarely This is especially conspicuous in seen in other species. p. XX younger slugs where they may Both features very often persist in be raised like lamellae (ridges). adults. Dark fringe lines never reach far into centre of sole.

A. (Arion) vulgaris

Usually a dirty orange or brick- Medium-sized red, often with dark grey spaces to very large Unbroken or broken lateral bands Usually same as body sides, Often a dark sooty grey, darker The rim around the between tubercles. (60 - 140 mm). conspicuous in juveniles, with area or a dirty orange. than the body sides. This is breathing pore is between lighter and more warmly diagnostic of A. vulgaris, although usually dark or black. Less variable than A. ater or A. coloured. paler soles often occur in the same A. (Arion) vulgaris A. (Arion) rufus but can vary from yellow to populations. Does not squirm red to brown to grey or (rarely) Body sides are often darker below the bands. from side to side p. XX black, even within a population. Dark fringe lines often reach far when retracted and Bands less often persist in adults than into centre of sole, which may also disturbed. dissection. by as juveniles, These are readily even distinguished and from A. ater A. rufus, in A. flagellus. have an orange flush.

A. (Arion) ater

Medium-sized Usually jet black in uplands, wetlands, and N. Scotland. to very large Paler sides Adults usually (60 - 140 mm). squirm from side to Elsewhere can vary from yellow Unless entirely black specimen, body Usually a darker or duller As dark or paler than body sides, side when retracted to red to brown to grey to black,

A. (Arion) ater A. (Arion) Tubercles more numerous and sides often paler than back. colour than body sides. May never darker. and disturbed. even within a population. less coarse than in A. flagellus. be a dirty orange. Body sides without lateral bands. Dark fringe lines often reach far Less likely to be seen N.B. Albinos are known from Scotland (faint banding may occur in juveniles) into centre of sole. and N. England. mating than other species. p. XX

A. (Arion) rufus Adults occasionally squirm from side to Medium-sized side when retracted to very large and disturbed. (60 - 140 mm). Often warmly coloured in southern lowlands, but can vary Mucus may have a from yellow to red to brown to Often brighter than body As dark or paler than body sides, faint orange tinge. A. (Arion) rufus A. (Arion) grey or (rarely) black, even within Body sides without lateral bands. sides, bright orange or never darker. a population. (faint banding may occur in juveniles) orange-red being common, but like other species may be Dark fringe lines often reach far p. XX a dirty orange. into centre of sole, which may also have an orange flush. after dissection. or even be distinguished externally, and A. rufus cannot! A. ater always

26 7. Adult size Body colour Tubercles Body markings Foot fringe colour Sole colour Other features Species

A. (Arion) flagellus Sometimes appears more flattened than other species. Medium-sized to large Often with an olive or green tint, Does not squirm (60 - 100 mm). a colour very rarely seen in other from side to side species. However, can vary from Tubercles fewer in number and Unbroken lateral bands conspicuous Usually same as body sides, Always as pale or paler than body when retracted and yellow to red to brown to grey to disturbed.

A. (Arion) vulgaris

A. (Arion) ater

27 8. Boettgerillidae & Milacidae

Body Shape Body Shape Rim of 8. Adult size Body colour Mucus Keel colour Sole colour Markings Species (extended) (Contracted) breating pore

Boettgerilla pallens

Small to medium-sized Colourless. Body white to pale blue-grey, (35 - 55 mm). becoming paler at sides. Same as body or slightly Uniformly pale Body unmarked, appearing Very slender and Not contrastingly paler darker. (although dark gut contents may relatively smooth. elongate, wormlike. than body sides. Identification of Slugs Identification show through translucent central p. XX Boettgerilla pallens Round in cross-section. Cylindrical. strip)

Milax gagates

Small to medium-sized Colourless. Body elephant-grey to brown (45 -55 mm). or black, becoming paler at Same as body or slightly Uniformly pale Body unmarked, appearing Less slender than other Hump-shaped. with keel Darker than body sides. Milax gagates sides. darker. (although dark gut contents may relatively smooth. species. Round to oval in raised. p. XX show through translucent central cross-section. strip)

Tandonia sp.

Small Body light yellow-grey to Colourless. (25 - 35 mm). brown- or blue-grey, becoming Lighter than body, yellow- Uniformly pale Dark pigment confined to Slender, elongate. Not contrastingly paler paler at sides. white. (although dark gut contents may grooves between tubercles, Round to oval in than body sides. Tandonia sp. Tandonia show through translucent central forming a very uniform cross-section. p. XX strip) reticulate (fishnet) pattern on tail and sides.

Tandonia budapestensis Elongate hump-shaped or often forming a C, or Medium-sized Colourless. U-shape at rest. (50 -70 mm). Body elephant-grey to dark Usually lighter than body, With pale sides, but usually Whole body densely “mottled” Slender, elongate. Not contrastingly paler grey-brown. Mantle usually often dirty yellow-orange. with dark pigment in the with minute dark spots. Dark Round to oval in than body sides. central strip. pigment in mantle grooves may cross-section. brown. p. XX form narrow black lines. Tandonia budapestensis Tandonia

Tandonia sowerbyi

Medium-sized Yellow to (60 - 75 mm). orange. Body yellow-grey to dark grey- brown. Usually lighter than body, Uniformly pale. Whole body densely “mottled” Less slender than other Hump-shaped, with keel Usually conspicuously often dirty yellow-orange. with minute dark spots. Dark species. Triangular in raised and sometimes paler than body sides.

Tandonia sowerbyi Tandonia pigment in mantle grooves may cross-section. crinkled. form narrow black lines. p. XX

Tandonia rustica

Medium-sized Colourless. (50 -70 mm). Body warm yellow-brown to Lighter than body, yellow- Uniformly pale. Whole body lightly speckled Less slender than other Hump-shaped. Usually conspicuously pale pinkish-brown. white. with black spots. Dark pigment species. Round to oval in paler than body sides. p. XX

Tandonia rustica Tandonia in mantle grooves may form cross-section. narrow black lines.

28 Body Shape Body Shape Rim of 8. Adult size Body colour Mucus Keel colour Sole colour Markings Species (extended) (Contracted) breating pore

Boettgerilla pallens

Small to medium-sized Colourless. Body white to pale blue-grey, (35 - 55 mm). becoming paler at sides. Same as body or slightly Uniformly pale Body unmarked, appearing Very slender and Not contrastingly paler darker. (although dark gut contents may relatively smooth. elongate, wormlike. than body sides. show through translucent central p. XX Boettgerilla pallens Round in cross-section. Cylindrical. strip)

Milax gagates

Tandonia sp.

Tandonia sowerbyi

Tandonia sowerbyi Tandonia pigment in mantle grooves may cross-section. crinkled. form narrow black lines. p. XX

Tandonia rustica

Tandonia rustica Tandonia in mantle grooves may form cross-section. narrow black lines. Identification of Slugs Identification

29 9. Limacidae: Genera

9. Adult size Body colour Sole colour Tentacles Mantle bands Other markings Mucus & body texture Other features Genus / species

Mucus: Only in old woodlands, including Malacolimax tenellus those replanted with conifers. Lightly tinged yellow or orange. Small More rarely in ancient wood- (35 - 50 mm). pasture. Identification of Slugs Identification Body texture:

Malacolimax Usually yellow, though can Dark brown, black Usually absent, with no markings Body unmarked. Noticeably soft and flaccid. Not yet known from Ireland. range from brown to orange. or violet. on the mantle. p. xx

(occasionally very indistinct brown bands may be visible)

Mucus: Limacus

Medium to large Colourless, or (mainly near Occurs in most habitats; (80 - 130 mm). Uniformly pale. head) tinged yellow or orange. sometimes found indoors.

Limacus Yellow, green, grey-green, or Blue-grey or grey. Mantle bands absent. Mantle Mantle and tail heavily blotched grey. usually mottled throughout. and spotted with green, grey- green or darker grey. Body texture: Go to Chart 10. Firm and muscular.

Mucus: Lehmannia & Ambigolimax

Colourless and very watery (even enough to make the slug slip Medium-sized

Ambigolimax around in the hand)

& (55 - 80 mm). Pale to dark brown; often Usually dark, but Often heavily blotched, banded May curl into a near ball-shape, greyish or pinkish but never never blueish. or spotted with dark brown, grey Body texture: tail folded towards head, when greenish. or black. Noticeably soft and flaccid. handled. Dark bands usually present, Go to Chart 11.

Lehmannia Lehmannia though may be indistinct or Occurs in most habitats. broken into spots.

Weak bands in small juveniles Mucus: Limax only.

Mantle mottled, spotty or entirely Large to without markings in adults. Occurs in most habitats; extremely large Colourless or very light yellow, and sticky rather than watery. sometimes found indoors. Limax (100 - 200 mm). Pale to dark brown or black; Uniformly pale, or Dark, often often greyish or pinkish but with dark edges red-brown. never greenish. contrasting with a Body texture: pale central zone. Firm and muscular. Body may be entirely unmarked Go to Chart 12. through to strongly marked with dark or black spots and blotches.

30 9. Adult size Body colour Sole colour Tentacles Mantle bands Other markings Mucus & body texture Other features Genus / species

Mucus: Only in old woodlands, including Malacolimax tenellus those replanted with conifers. Lightly tinged yellow or orange. Small More rarely in ancient wood- (35 - 50 mm). pasture. Body texture:

(occasionally very indistinct brown bands may be visible)

Mucus: Limacus

Medium to large Colourless, or (mainly near Occurs in most habitats; (80 - 130 mm). Uniformly pale. head) tinged yellow or orange. sometimes found indoors.

Mucus: Lehmannia & Ambigolimax

Colourless and very watery (even enough to make the slug slip Medium-sized

Ambigolimax around in the hand)

Lehmannia Lehmannia though may be indistinct or Occurs in most habitats. broken into spots.

Weak bands in small juveniles Mucus: Limax only.

31 10. Limacidae: Limacus

10. Limacus flavus Limacus maculatus

Medium to large Medium to large (80 - 130 mm). (80 - 130 mm). Adult size Adult Identification of Slugs Identification

Yellow-green to yellow-brown; colours often warmer and sometimes Pale ochre, green, grey or blackish. paler than in L. maculatus. Body colour

Body and tail slender; tapering gradually to tail tip. Body and tail plump and cylindrical throughout; tapering more Shape & markingsShape acutely to tail tip Mantle and tail blotched and spotted. Tail with a central pale stripe on the keel , often extending further than the keel itself. Mantle and tail heavily blotched and spotted. Tail without a pale stripe on the keel (except in juveniles under 20 mm). Tubercles

Often finer less coarse than in L. maculatus Often coarser than in L. flavus

Mucus Usually yellow May be colourless or yellow to orange

Found exclusively near buildings, including indoors. Habitat as for L. flavus, including indoors, but also found in woods Widespread but now much less common than L. maculatus. etc. far from standing buildings.

Appears to be less gregarious when resting than L. maculatus. Gregarious when resting (only noticeable when several animals are present!) Other features

Limacus flavus Limacus maculatus Species

p. xx p. xx

32 11. Limacidae: Lehmannia & Ambigolimax

11. Lehmannia marginata Ambigolimax valentiana Ambigolimax nyctelia

Medium-sized Medium-sized Medium-sized (60 - 90 mm). (50 - 80 mm). (55 - 70 mm). Adult size Adult

Variable, pale grey to ochre or brown, Variable, pale grey to brown but usually with a distinct pinkish tinge. without a pinkish tinge.

Body colour Almost translucent in wet conditions.

central stripe Prominent dark markings

pale keel

Markings Usually with diffuse dark markings, including Usually with faint dark markings, including Usually with prominent dark markings, blotches, spots, and/or faint lateral bands. blotches, spots, and/or faint lateral bands including blotches, spots, and/or faint high on the body running as tramlines down lateral bands high on the body running as Tail with a central pale stripe on the keel , the tail. Often with three mantle bands. tramlines down the tail. Often with three often extending further than the keel itself. mantle bands. Markings usually darker than Keel same colour as body. in A. valentiana. Keel same colour as body.

Colourless; watery and copious when Colourless; less watery and less copious than in L. marginata. handled. Mucus

Readily climbs trees, cliffs and walls in wet Little tendency to climb trees, cliffs or walls. conditions. Mainly in disturbed lowland habitats, including urban gardens, compost heaps and Mainly in wilder habitats, including woods, greenhouses and roadsides. However, now spreading into woods. rocky uplands (to mountain summits) and

Other features sea cliffs.

Lehmannia marginata Ambigolimax valentiana Ambigolimax nyctelia Species

p. xx p. xx p. xx ! L. valentiana and L. nyctelia cannot usually be distinguished without dissection.

! Upon dissection, L. nyctelia may be further divided into two species. of Slugs Identification

33 12. Limacidae: Limax

12. Limax maximus Limax cinereoniger Limax sp.

Large to very large Large to very large Very large (100 – 150 mm). (100 – 150 mm). (130 – 150 mm). Adult size Adult Identification of Slugs Identification

Pale ochre, brown, grey or blackish. Pale ochre, brown, grey or blackish. Pale ochre. Body colour Keel

Short, running less than half of tail length. Long, running half or more of tail length. Usually paler in colour than body.

Always uniformly pale. Often with dark stripes at sides with a pale Dark stripes at the sides with pale central Sole colour central strip, but may be uniformly pale strip. Contrast becoming more prominent throughout. towards the tail. Tubercles Relatively small and fine. Relatively larger and coarse (noticeable even in juveniles).

Usually with dark blotches or spots. Often Never present on mantle. Markings, if present, only ever confined to tail. Mantle markingsMantle heavily marked. Never banded. Tentacles

Reddish-brown, without dark speckles. Grey-brown, with dark speckles. Pale, without dark speckles.

Common in urban gardens and other Rare in gardens and other disturbed areas Known from one ornamental woodland in disturbed areas; may enter buildings Mainly in old woodlands; also in uplands E. Yorkshire Also in wilder habitats, especially woods; and on sea cliffs. rarely in uplands or sea cliffs. May show unusual back and forth “lurching” behaviour when disturbed. Other features Limax maximus Limax cinereoniger Limax sp. Species

p. xx p. xx p. xx

34 13. Agriolimacidae: Deroceras

Deroceras Deroceras 13. Deroceras laeve Deroceras reticulatum invadens/panormitanum agreste/reticulatum

Very small Small Small Small (15 - 25 mm). (25 - 35 mm). (35 - 50 mm). (25 - 45 mm). Adult size Adult

From pale chestnut or mid-grey to very dark brown. From white, through buff to Pale magnolia to buff, often with Organs may show through slightly translucent mantle, especially in brown or grey. a warm (“sun-tanned”) tone. D. invadens and D. panormitanum. Body Cololur

Watery and colourless. Milky when handled (may be released more reluctantly by populations on acidic soils). Mucus

Mantle ridges Mantle Coarse, broadly spaced. Fine, closely spaced and more numerous.

Tail Mantle Tail Mantle

Tail : Mantle Tail Tail equal to or shorter than Tail noticeably longer than mantle. mantle. Tail tip Tail Tail often very steeply truncate. Tail less steeply truncate.

Not contrastingly paler than Usually conspicuously paler than Not usually contrastingly paler than body sides. body sides. body sides. Rim of breathing pore Rim of breathing

Often with minute black speckles or larger flecks, easily overlooked Usually flecked with dark No trace of darker pigment

Markings without a lens. pigment. markings. Pigment between tubercles may form a reticulate (fishnet) pattern on tail and sides.

Deroceras laeve Deroceras invadens Deroceras reticulatum Deroceras agreste

or or Species

Deroceras panormitanum Deroceras reticulatum

p. XX p. xx & p. xx p. XX p. xx & p. xx of Slugs Identification

35 14. Testacellidae: Testacella

14. Testacella maugei Testacella haliotidea Testacella scutulum Testacella sp. Shell

Large (XX – XX x XX – XX mm), Small (XX – XX x XX – XX mm), Small (XX – XX x XX – XX mm), flattened and triangular. oblong; Noticibly convex. slightly convex. Identification of Slugs Identification

Grey-brown, rarely red-brown Grey-white or creamy-white to Pale yellow to rich orange-yellow. Body colour or black. pale yellow; centre of back light brown. Densely speckled with dark pigment. Very densely speckled with dark pigment. Unspeckled, or only lightly speckled with brown.

Sole colour Salmon-pink to orange. Whitish, like body. Yellow to rich orange-yellow. Dorsal grooves Dorsal grooves far apart at Dorsal grooves close together Dorsal grooves usually combine just before junction with shell. junction with shell. but still separate at junction with shell.

When extended, body less flattened than other species. Almost When extended, body more flattened than other species.

Body shape wedge-like.

Body sides relatively smooth; Body sides with parallel oblique Body sides relatively smooth; oblique grooves present but hard to

Body texture oblique grooves present but grooves (like a fish steak) often discern. hard to discern. clearly visible.

Testacella maugei Testacella haliotidea Testacella scutulum Testacella sp. Species p.xx p.xx p.xx p.xx

36 15. Vitrinidae

15. Semlimax pyrenaicus Vitrina pellucida Phenacolimax major

Very small (XX – XX mm). Vey small (XX – XX mm). Very small (XX – XX mm). Adult size Adult Shell

Ear-like, flattened. More snail-like than S. pyrenaicus. (for further details see AIDGAP snails key)

Mantle Mantle Mantle

Mantle lobe Mantle lobe Mantle lobe Mantle

Mantle pale grey to brown, with dark Mantle pale grey, usually pale. Mantle usually dark with slight mottling. mottling. Mantle lobe barely extends on to shell. Mantle lobe extends well onto shell, nearly Mantle lobe covers apex of shell reaching apex.

Widespread but local in Ireland (not in Common and widespread throughout Rare; generally ancient woodlands in Britain) Britain and Ireland southern Britain (not in Ireland) Adults living mainly in winter Adults living mainly in summer Other features

Semilimax pyrenaicus Vitrina pellucida Phenacolimax major Species

p.xx p.xx p.xx Identification of Slugs Identification

37 Slugs of Britain and Ireland (Short test version)

This new AIDGAP key to slugs is being tested over the next few months. Please try the key out and see how easy you find it to use. Only the identification charts are included here for testing. The finished work will include introductory text and species descriptions. Feedback from testers is a critical part of the AIDGAP project . We value all your comments on the keys accuracy, ease of use etc, whether these are critical or otherwise. The authors will revise the final version in light of this feedback, so all comments are potentially useful. Please either email your comments to [email protected] or complete the form and post it to: FSC Publications, Unit C1, Stafford Park 15, Telford TF3 3BB

Thank you for your support of the AIDGAP project.

AIDGAP TEST VERSION - Slugs of Britain and Ireland

1 – What type of identification guides have you used before?

2 - Did you find this Guide easy to use? YES / NO

3 – Were you confident that your identifications were correct? YES / NO (please comment)

4 – Did you find any parts of the guide difficult or misleading? YES / NO (please comment)

5 – Were there sufficient illustrations? YES / NO (please comment)

6 – Are there any changes you would like to see made before final publication? (please comment)

7 – Is there any additional information that you would like to see included?

8 - Any additional comments?

Name: Please return by 20th JULY 2013