Arion ater

Arion ater is a terrestrial slug, common in England and the Pacific Northwest. (BBC 2000).

Biogeographic Regions: nearctic (Native ); palearctic (Native )

Native to: British Isles, N and central Europe, Iceland, Russia (Quick 1960).

Non-native to: North America (Quick 1960).

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Although thought to be shell-less snails, Arion ater do have disc-type shells embedded in their mantle. This is surrounded by a fleshy oval tissue on their back. Slugs move about via a foot that, when flexed, allows the slug to control its movement.

Most Arion ater are orange when hatched, have a "straw" coloration until aproximately one inch in length, and eventually take on a black coloration. Typical slugs are about six inches long at maturity. (Branley 1996).

External: Largest Arion slug; varies greatly in color from black (northerly or mountain forms) to brown, red, orange or gray (southerly or cultivated land forms); foot fringe tends to be redder than body, with darker transverse lines; gray sole; large skin tubercles; big pneumostome; sticky body mucus may be clear or yellow; can form a hemisphere when contracted (Quick 1960; Kerney & Cameron 1979).

Internal: Ring at base of epiphallus where it enters the atrium; short free oviduct is surrounded by genital retractor; ligula (internal folds) in upper atrium; 18 mm long spermatophore, with serrations along its length and tapered at ends (Quick 1960; Kerney & Cameron 1979).

Atrial ligula is much smaller than in A. rufus (Quick 1960).

Juveniles: Sometimes have lateral bands; 10 mm long and pale yellow or greenish at hatching, gaining pigmentation as they age (Quick 1960; Kerney & Cameron 1979).

Eggs: 5 x 4 mm; opaque; turn pearly white to brown with age; up to 150 eggs per clutch (Quick 1960).

100-150 mm long extended (Quick 1960).

Arion rufus

Arion ater prefer grassy fields and crops of vegetation. Strictly terrestrial, they typically live in moist, cool soil (Long 1999).

Terrestrial Biomes: savanna or grassland

Grasslands, forests, hedges, gardens, wastelands, bogs; to 1800 m altitude (Quick 1960; Kerney & Cameron 1979). Microhabitat is mostly living plants, with some occupying bare soil or dead plants and logs when available (Cameron 1978).

Habitat Type: Terrestrial

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Arion ater spend most of their time eating. This is done with an enclosed radula that contains transverse rows of sharp teeth. The slug's diet consists mostly of fungi and plants, but is occasionally supplemented by worms, insects, decaying vegetation, and feces. Slugs feed mostly at night when conditions are cool and moist (Long 1999).

Omnivorous. Feed on dead and live plants, dead animals, and feces (Graham 1955; Chatfield 1976).

Preyed upon by lampyrid beetle larvae (Schwalb 1961, in Stephenson & Knutson 1966).

Not aggressive (Rollo & Wellington 1979). Aggregations of A. ater occurs during dry conditions and unfavorable temperatures (Rollo & Wellington 1981).

For defense, A. ater may contract its body and rock from side to side (Kerney & Cameron 1979).

Slugs, like snails, are hermaphrodites. It can fertilize itself, but prefers a mate. The slug then lays eggs about 5 mm in diameter. The eggs are usually laid in dark and damp areas.

Although Arion ater are hermaphroditic, they do engage in cross-fertilization when a mate is available. After copulation, the slug may lay 20-50 eggs in crevices made in soil or in the cracks of decaying wood. These eggs typically hatch in six weeks (BBC 2000).

Key Reproductive Features: simultaneous hermaphrodite; sexual ; fertilization (Internal ); oviparous

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There is 1 barcode sequence available from BOLD and GenBank.   Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen.  Other sequences that do not yet meet barcode criteria may also be available.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Specimens with Barcodes: 5
Species With Barcodes: 1

This species is given no special conservation status.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G5 - Secure

Slugs are often a nuisance to horticulturists because of their choice of diet. Lettuce is a crop that is heavily damaged by slugs. Any sort of vegetation is at risk to slug damage. Arion ater is considered to be among the most destructive of the slugs (Long 1999).

In general, slugs are crucial to a healthy ecosystem. They work to recycle decaying food and fecal matter that is then processed back through the soil. Without slugs working in such a manner, soil could potentially lose many of its nutrients (Nickel 1998).