Deroceras laeve

Deroceras laeve
Deroceras laeve
Conservation status
NE[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Heterobranchia clade Euthyneura clade Panpulmonata clade Eupulmonata clade Stylommatophora informal group Sigmurethra clade limacoid clade
Superfamily:	Limacoidea
Family:	Agriolimacidae
Genus:	Deroceras
Species:	D. laeve
Binomial name
Deroceras laeve (O. F. Müller, 1774)[2]
Synonyms[3]
Limax lævis Müller, 1774 Limax brunneus Draparnaud, 1801 Limax (Deroceras?) gracilis Rafinesque, 1820 Limax campestris Binney, 1842 Limax parvulus Normand, 1852 Limax Weinlandi Heynemann, 1862 Limax araneus Gessis, 1867 Agriolimax bovenoti Collinge, 1870 Limax castaneus Ingersoll, 1875 Limax ingersolli Binney, 1875 Limax montanus Ingersoll, 1875 Limax hyperboreus Westerlund, 1876 Krynickillus montanus Nevill, 1880 Limax hemphilli Binney, 1890 Limax berendti var. pictus Cockerell, 1897 Agriolimax pseudodiocus Velichkovskiy, 1910 Agriolimax (Hydrolimax) renschi Wagner, 1934

Deroceras laeve, the marsh slug, is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Agriolimacidae.

Distribution

The distribution of Deroceras laeve was originally Palearctic, from the subpolar zones to the southern margins.^[4] Today this slug species has been introduced worldwide except Antarctica, also on tropical islands such as New Guinea and on Pacific islands.^[4]

Europe:

• British Isles: Great Britain and Ireland. The species has shown little evidence for significant decline in Britain.^[4]
• Czech Republic^[5] - least concern (LC) ^[6]
• Netherlands ^[7]
• Poland
• Slovakia^[5]
• Sweden
• Switzerland - lower concern in Switzerland^[4]
• and others

Asia:

• Pakistan^[8]
• China^[9]
• Taiwan^[10]

The Americas:

• California^[11]
• El Hatillo Municipality, Miranda, Venezuela
• Colombia^[12]
• introduced to Dominica (first report in 2009)^[13]
• and others

Description

The slug is from brown to dark brown, usually with dark and characteristic but not well visible spots arranged in groups.^[4] The shape is almost cylindrical, posterior end is abruptly widened.^[4] The mantle covers 50 % of body length (unusually large).^[4] There are wrinkles on skin present (may disappear in preserved slugs).^[4] Mucus is thin, colourless.^[4]

This slug is 15–25 mm long when preserved.^[4]

The populations of this species that occur in Central Europe are much darker than other Deroceras species in that area.^{[citation needed]}

Drawing of the reproductive system of Deroceras laeve
a - atrium
v - vagina
p - penis
mr - musculus retractor penis
bc - bursa copulatrix.

Reproductive system: Penis is often reduced, elongated if present, without proper penial gland but with two or more tiny glandular papillae and its end.^[4] Retractor is unforked and attached at half penis length, stimulator small, cone-shaped but looks more like a papilla.^[4] Tubular oviductus and atrium are unusually long.^[4] There is no rectal caecum.^[4]

Epithelium of Deroceras laeve

Ecology

Habitat

Deroceras laeve has high ecological tolerance, but needs permanently wet habitats.^[4] It is usually found in lowlands and very humid habitats, swamps, riversides, wetlands, especially alder and oak woods, marshlands and degraded areas, also greenhouses, often near water under wood or detritus.^[4] It tolerates subpolar and tropical temperatures.^[4] Newly created habitats are often colonized after a few years.^[4] In Switzerland in up to 1800 m altitude, but usually below 1000 m, in Bulgaria in up to 2500 m.^[4]

Deroceras laeve can be a serious pest in greenhouses.^[4] On the other hand the species is threatened by continuous elimination of wet habitats by drainage, construction projects and road construction.^[4]

It is the only land gastropod that goes deliberately into the water and can survive for days submerged.^[4] Because of this unusual behavior, the species can be dispersed by flowing water.^[4]

Feeding habits

These slugs are agile and crawl quickly. They are omnivorous, but live and dead plant remains are preferred.^[4]

Life cycle

The eggs of this species can also survive when submerged; juveniles can hatch underwater and then climb to the surface.^[4]

The life cycle is extremely short, and can take place within less than a month.^[4] This species can have up to 5 generations in a year,^[4] with several generations alive at the same time.^[4] Frequently there are forms with a reduced penis, which reproduce by self-fertilisation.^[4] The maximum age of this slug is not more than 1 year.^[4]

Parasites

Parasites of Deroceras laeve include:

• Parelaphostrongylus tenuis^[14]

References

This article incorporates public domain text from the reference ^[4]

1. ^ (2006). IUCN Red List of Threatened Species. <www.iucnredlist.org>. Cited 2 March 2007.
2. ^ Müller O. F. (1774). Vermivm terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volumen alterum. pp. I-XXXVI [= 1-36], 1-214, [1-10]. Havniæ & Lipsiæ. (Heineck & Faber).
3. ^ "Synonyms of Limax laevis (n=17)". AnimalBase, accessed 4 January 2011.
4. ^ ^{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} Species summary for Deroceras laeve. AnimalBase, accessed 4 January 2011.
5. ^ ^{a b} (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.
6. ^ Juřičková L, Horsák M, Beran L (2001). "Check-list of the molluscs (Mollusca) of the Czech Republic". Acta Soc. Zool. Bohem. 65: 25–40. 
7. ^ http://www.anemoon.org/anm/voorlopige-kaarten/landmollusken/wetenschappelijk/deroceras-laeve/
8. ^ Hlaváč, J. Č. (2004). "A new record of Deroceras laeve (O. F. Müller, 1774) from Pakistan (Gastropoda: Pulmonata: Agriolimacidae)". Folia Malacologica 12: 181–182. 
9. ^ Wiktor, A.; De-niu, C.; Wu, M. (2000). "Stylommatophoran slugs of China (Gastropoda: Pulmonata) – prodromus". Folia Malacologica 8 (1): 3–35. 
10. ^ Tsai C.-L. & Wu S.-K. (2008). "A New Meghimatium Slug (Pulmonata: Philomycidae) from Taiwan". Zoological Studies 47(6): 759-766. PDF.
11. ^ Rory J. Mc Donnel, Timothy D. Paine & Michael J. Gormally (2009). Slugs: A Guide to the Invasive and Native Fauna of California. ISBN 978-1-60107-564-2. http://anrcatalog.ucdavis.edu/Items/8336.aspx. 
12. ^ Hausdorf B (May 2002). "Introduced land snails and slugs in Colombia". J. Molluscan Stud. 68 (2): 127–131. doi:10.1093/mollus/68.2.127. PMID 12011238. 
13. ^ Robinson D. G., Hovestadt A., Fields A. & Breure A. S. H. (July 2009). "The land Mollusca of Dominica (Lesser Antilles), with notes on some enigmatic or rare species". Zoologische Mededelingen 83 http://www.zoologischemededelingen.nl/83/nr03/a13
14. ^ Michigan Department of Natural Resources and Environment. "Brainworm". accessed 14 December 2010.

External links

• Deroceras laeve on the UF / IFAS Featured Creatures Web site