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Deroceras reticulatum
	Adult Deroceras reticulatum
Conservation status
	; Least Concern (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Stylommatophora
Family:	Agriolimacidae
Genus:	Deroceras
Species:	D. reticulatum
Binomial name
	Deroceras reticulatum; (O. F. Müller, 1774)
Synonyms
	Agriolimax reticulatus (Müller, 1774) Limax reticulatus Müller, 1774

Deroceras reticulatum, common names the "grey field slug", "grey garden slug", and "milky slug", is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusc in the family Agriolimacidae. This species is an important agricultural pest.

Distribution

Deroceras reticulatum is native to Europe, North Africa and the Atlantic Islands.^[2]^[3] It occurs widely in Europe, but is more rare and restricted to cultivated fields in the southeast, particularly in the Balkans, and is probably absent from Greece and the Bulgarian mountains.^[2] In the north and central European lowlands, Great Britain, and Ireland, it is probably the most widely occurring slug.^[2] In northern Scandinavia it is scarce, and is mainly found as a synanthrope.^[2]

This species occurs in countries and islands including:

Great Britain
Ireland
Austria
Spain
Bulgaria
Czech Republic^[4] – least concern (LC)^[5]
Netherlands^[6]
Poland
Slovakia^[4]
Sweden
Latvia
Ukraine^[7]

The species has been widely introduced as a synanthrope to many regions:

North America,^[2] in parts of Northern Michigan and Southern Michigan
Canada^{[citation needed]}
Colombia^[8]
Peru^[2]
Argentina – major slug pest in Buenos Aires province^[9]
Saint Helena^[10]
Tasmania^[2]
New Zealand^[2]
central Asia^[2]

Description

As all other Deroceras it has a short keel at the back of the body. Deroceras reticulatum is very variable in colour, creamy or light coffee cream, rarely blackish spotted (slugs with spots may appear blackish).^[2] Behind the mantle there is the dark spots form a reticulate pattern.^[2] The skin is thick.^[2] Mucus is colourless, on irritation milky white.^[2] The slug cannot be distinguished from many other Deroceras species based only on its external appearance.^[2]

This slug can be up to 40–60 mm long (preserved 25–30 mm).^[2] The size varies according to the habitat.^[2]

Reproductive system: Penis is fleshy and with a silky sheen, in the shape of an irregular sac, in fully mature specimens divided into 2 parts by a deep lateral constriction.^[2] Penial gland has very variable shape, usually a few branches or a single long branch.^[2] Stimulator is large, conical and narrow.^[2] Retractor of the penis is inserted laterally.^[2] Vas deferens opens into penis wall facing the external body side.^[2] Rectal caecum is large.^[2]

This slug can travel up to 40 feet (12.2 m) in one night.^[11]

Ecology

Habitat

Deroceras reticulatum is almost exclusively restricted to cultivated areas, usually in open habitats, in meadows, near roadsides, in ruins, gardens and parks, not inside forests.^[2] External appearance is very similar to Deroceras rodnae, Deroceras praecox and the internal anatomy is very similar to Deroceras turcicum, but those three species lives in natural habitats – in woods – and they co-occur with Deroceras reticulatum very rarely.^[3] It shelters under stones and ground litter (It does not burrow into the soil).^[2] It is active at night.^[2]

Feeding habits

This species is omnivorous, feeding mainly on fresh leaves and fruits or seedings.^[2] Deroceras reticulatum is a serious pest of agricultural crops, garden cultivations^[2] and horticulture.^[11] After several years with continuous moist weather conditions abundance can seriously increase.^[2]

Life cycle

Life cycle covers a few months, usually two generations.^[2] The main reproductive phase is in summer and autumn.^[2] It lays hundreds of eggs which hatch during early summer.^[11]

Maximum age is about a year.^[2] Slugs die at the first frosts.^[2] Usually only eggs hibernate, sometimes also juveniles.^[2]

Predators

Various carabid beetles are predators of Deroceras reticlatum, including:

the European garden beetle Carabus nemoralis, is a beneficial predator (from the human perspective) because it eats the young of this species and also their eggs.^[11]
Pterostichus melanarius^[12]
Pterostichus madidus^[9]
Nebria brevicollis^[9]
Scarites anthracinus eats eggs and slugs in Argentina.^[9]
Poecilus cupreus^[12]

Parasites

The bacterium Moraxella osloensis is a mutualistic symbiont of the slug-parasitic nematode Phasmarhabditis hermaphrodita.^[13] In nature, Phasmarhabditis hermaphrodita vectors Moraxella osloensis into the shell cavity of the slug host Deroceras reticulatum in which the bacteria multiply and kill the slug.^[13]

Deroceras reticulatum can transfer Escherichia coli on its body surface.^[14]

Parasites of Deroceras reticulatum include:

Parelaphostrongylus tenuis^[15]

References

This article incorporates CC-BY-2.0 text from the reference ^[13] and public domain text from the reference.^[2]

^ Müller O. F. (1774). Vermivm terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volumen alterum. pp. I-XXXVI, 1–214, [1–10]. Havniae & Lipsiae. (Heineck & Faber).
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai "Species summary for Deroceras reticulatum". AnimalBase, last modified 29 August 2010, accessed 10 December 2010.
^ ^a ^b Horsák M., Juřičková L. & Picka J. (2013). Měkkýši České a Slovenské republiky. Molluscs of the Czech and Slovak Republics. Kabourek, Zlín, 264 pp. (in Czech and English).
^ ^a ^b (in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. (2010). "Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]". Malacologica Bohemoslovaca, Suppl. 1: 1–37. PDF.
^ Juřičková, L.; Horsák, M.; Beran, L. (2001). "Check-list of the molluscs (Mollusca) of the Czech Republic". Acta Soc. Zool. Bohem. 65: 25–40.
^ "Anemoon > Flora en Fauna > Soorteninformatie". www.anemoon.org.
^ Balashov I. & Gural-Sverlova N. 2012. An annotated checklist of the terrestrial molluscs of Ukraine. Journal of Conchology. 41 (1): 91–109.
^ Hausdorf B. (May 2002). "Introduced Land Snails and Slugs in Colombia" (PDF). Journal of Molluscan Studies. 68 (2): 127–131. doi:10.1093/mollus/68.2.127. PMID 12011238. Archived from the original (PDF) on 2 November 2006.
^ ^a ^b ^c ^d Tulli M. C., Carmona D. M., López A. N., Manetti P. L., Vincini A. M. & Cendoya G. (2009). "Predation on the slug Deroceras reticulatum (Pulmonata: Stylommatophora) by Scarites anthracinus (Coleoptera: Carabidae)". Ecología Austral. 19: 55–61. PDF.
^ Crowley, T.E. & Pain, T. 1977. Mollusca not Charopidae. pp. 534–575, pl. 9–10. In: Basilewsky, P. (Ed.). La faune terrestre de l'île de Sainte-Hélène. Quatrième partie. Annales du Musée Royal de l'Afrique Centrale, Zoologie. 220:1–575.
^ ^a ^b ^c ^d "PACIFIC NORTHWEST NURSERY IPM. Snails/Slugs". Oregon State University, last modified 29 July 2005.
^ ^a ^b Oberholzer F. & Frank T. (2003). "Predation by the carabid Beetles Pterostichus melanarius and Poecilus cupreus on Slugs and Slug Eggs". Biocontrol Science and Technology 13(1): 99–110. doi:10.1080/0958315021000054421.
^ ^a ^b ^c An R., SreevatsanS. & Grewal P. S. (2008). "Moraxella osloensis Gene Expression in the Slug Host Deroceras reticulatum". BMC Microbiology 8: 19. doi:10.1186/1471-2180-8-19.
^ Sproston, E. L.; MacRae, M.; Ogden, I. D.; Wilson, M. J.; Strachan, N. J. C. (2006). "Slugs: Potential Novel Vectors of Escherichia coli O157". Applied and Environmental Microbiology. 72 (1): 144–149. Bibcode:2006ApEnM..72..144S. doi:10.1128/AEM.72.1.144-149.2006. PMC 1352200. PMID 16391036.
^ Michigan Department of Natural Resources and Environment. "Brainworm". accessed 14 December 2010.

Spencer, H.G., Marshall, B.A. & Willan, R.C. (2009). Checklist of New Zealand living Mollusca. pp 196–219 in Gordon, D.P. (ed.) New Zealand inventory of biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch