Deroceras reticulatum

Family

Agriolimacidae

Species

Deroceras reticulatum (O.F. Muller, 1774)

Common Name

Grey fieldslug, Field slug, Milky slug

Description

A mature grey fieldslug ranges in length from 35 to 50 mm. The stout body of this slug may be cream-colored, greyish or has a slight pink-grey color. The mantle has concentric striations and usually covers more than one-third the length of the slug. There are dark brown or grey flecks concentrated between the tubercles. The tentacles are dark in color. The thin, clear, sticky mucus of this slug often becomes a milky white when it is harassed. There is a short keel at the tail end. The sole of the foot is tripartite, whitish to grey-yellow in color with the median field grey. The pneumostome ( breathing pore) having a raised, pale border is located in the posterior forth of the mantle. This species can easily be confused with Deroceras agreste. In order to confirm the identity of this species, dissection and observation of the genitalia are required.

Deroceras agreste. The penis (p) of this species is broad with only a single appendix.

Deroceras caucasicum: The penis is broad and has two appendixes at the tip with the vas deferens emerges between them. The posterior edge of the penis is pigmented (dark-colored) and there is a hard "clam-shaped" shell-like plate inside the penis.

Deroceras laeve: The penis of this species is long, narrow and mostly twisted, with only a single appendix. It should be noted that a penis may be absent in some specimens.

Deroceras panormitanum: The penis in the species is broad and markedly bilobed with 4-6 appendixes.

Deroceras reticulatum: The penis (p) in the species is broad with only a single, irregularly branched appendix.

Native Range

Western Europe

Distribution

North America:

  • U.S.: Alabama, California, Colorado, Hawaii, Illinois, Kentucky, Michigan, Ohio, Oklahoma, Utah, Washington, Wisconsin, Wyoming
  • Canada: Newfoundland, Quebec, Ontario, British Columbia

Asia: Sri Lanka

Australasia: New Zealand

Europe

Ecology

This slug prefers modified habitats, such as garden, greenhouses, roadsides and fields. The diet of D. reticulatum is primarilly constituted of living plant material but this slug is an omnivore and may consume mushrooms, dead slugs, earthworms and other animal matter. This species is especially destructive to seedlings and succulent plants. In northern Europe and North America this species damages grains, clover and vegetable crops. This slug has the potential to detect predatory carabid beetles through the use of olfactory cues. When attacked, the slug lashes its tail, secretes copious amounts of mucus and flees its attacker. The slug may also amputate the tip of its tail to evade predation. Reproduction is by cross-fertilization and occurs year round under favorable conditions. Mating occurs mainly at night and approximately 60-75 eggs (4 mm each) are produced per clutch totaling approximately 700 eggs per year per specimen. The animal’s lifespan is generally one to two years.

Synonyms

  • Limax agrestis Linnaeus, 1758. Syst. Nat. 1: 1082 (part).
  • Limax reticulatus Muller, 1774 Verm. Terr. Et fluv. Hist., 2:10 (gardens of Rosenburg and Fridricksdal).
  • Limax canariensis d'Orbigny, 1839. Hist. NAt. Iles Canaries (Webb and Berthelot) 2(2): 47.
  • Limax tunicata Gould, 1841, Invert. of Mass. p. 3 (Massachusetts).
  • Krynickillus minutus Kalenickzenko, 1851. Bull. Soc. Imp. Nat. Moscou 24: 224.
  • Limax agrestis Leidy, 1851, in Binney, Terr. Moll., 1: 250, pl. 2, figs. 7-9 (anatomy); Binney, 1851, Terr. Mol. 2: 36, pl. 64, fig. 2.; W.G. Binney, 1878. Terr. Moll. 5:146. Not Limax agrestis Linnaeus, 1758, Syst. Nat. (10) p. 652, as restricted by Luther.
  • Limax molestus Hutton, 1879. Trans. N.Z. Inst. 11: 331 (new synonymy).
  • Krynickillus niciensis (Boettger) Nevill, 1880. Proc. Zool. Soc. Lond.: 103.
  • Agriolimax agrestis L. of most authors in the last century; Cockerell , 1891, Nautilus, 5: 70 (named color-varieties); 11: 15, fig. 1 (monstrosity); 7:21 (in Jamaica)
  • Agriolimax reticulatus Muller, Luther, 1915 Actes fauna et flora Fennica, 40, No. 2.; Ingram, 1943, Nautilus, 55:67.

References

Anderson 2005; Barker 1879; Branson 1959; Branson 1962; Branson 1980; Carrick 1942; Cowie 1997; Cowie et al. 2009; Forsyth 2004; Horsak 2004; Hutchinson and Heike 2007; Kerney et al. 1979; Naggs et al. 2003; Pilsbry 1939; Thomas et al. 2010; Wiktor 2000

Posted on 09 - 02 - 11