Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Deroceras laeve
(meadow slug)

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Datasheet

Deroceras laeve (meadow slug)

Summary

  • Last modified
  • 15 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Natural Enemy
  • Preferred Scientific Name
  • Deroceras laeve
  • Preferred Common Name
  • meadow slug
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Mollusca
  •       Class: Gastropoda
  •         Subclass: Pulmonata
  • Summary of Invasiveness
  • D. laeve is native to the Palaearctic and to at least the western half of the Nearctic. This species is frequently confused with other species in the genus Deroceras, in particular D. invadens. ...

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Pictures

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PictureTitleCaptionCopyright
Deroceras laeve (meadow slug); from marshland. County Down, Northern Ireland, UK.
TitleAdult
CaptionDeroceras laeve (meadow slug); from marshland. County Down, Northern Ireland, UK.
Copyright©Roy Anderson
Deroceras laeve (meadow slug); from marshland. County Down, Northern Ireland, UK.
AdultDeroceras laeve (meadow slug); from marshland. County Down, Northern Ireland, UK.©Roy Anderson
Deroceras laeve (meadow slug); from alder carr. County Antrim, Northern Ireland, UK.
TitleAdult
CaptionDeroceras laeve (meadow slug); from alder carr. County Antrim, Northern Ireland, UK.
Copyright©Roy Anderson
Deroceras laeve (meadow slug); from alder carr. County Antrim, Northern Ireland, UK.
AdultDeroceras laeve (meadow slug); from alder carr. County Antrim, Northern Ireland, UK.©Roy Anderson
Deroceras laeve (meadow slug); greenhouse form. Belfast, Northern Ireland, UK.
TitleAdult
CaptionDeroceras laeve (meadow slug); greenhouse form. Belfast, Northern Ireland, UK.
Copyright©Roy Anderson
Deroceras laeve (meadow slug); greenhouse form. Belfast, Northern Ireland, UK.
AdultDeroceras laeve (meadow slug); greenhouse form. Belfast, Northern Ireland, UK.©Roy Anderson
Deroceras laeve (meadow slug); from woodland. County Dublin, Republic of Ireland.
TitleAdult
CaptionDeroceras laeve (meadow slug); from woodland. County Dublin, Republic of Ireland.
Copyright©Roy Anderson
Deroceras laeve (meadow slug); from woodland. County Dublin, Republic of Ireland.
AdultDeroceras laeve (meadow slug); from woodland. County Dublin, Republic of Ireland.©Roy Anderson

Identity

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Preferred Scientific Name

  • Deroceras laeve Müller

Preferred Common Name

  • meadow slug

Other Scientific Names

  • Agriolimax agrestis L.
  • Agriolimax berendti var. pictus Cockerell
  • Agriolimax bovenoti Collinge
  • Agriolimax campestris zonatipes Cockerell
  • Agriolimax globosus Collinge
  • Agriolimax pellucidus Chen & Gao
  • Agriolimax perkinsi Collinge
  • Agriolimax pseudodioicus Velitchkovsky
  • Agriolimax renschi Wagner
  • Deroceras schulzi Y. Tzvetkov & Matyokin
  • Krynickillus minutus Kaleniczenko
  • Limax agrestis L.
  • Limax araneus Gessis
  • Limax berendti var. pictus Cockerell
  • Limax brunnaeus Draparnaud
  • Limax brunneus Draparnaud
  • Limax campestris A. Binney
  • Limax castaneus Ingersoll
  • Limax fedtschenkoni Koch & Heynemann
  • Limax gracilis Rafinesque
  • Limax hemphili W.G. Binney
  • Limax heydeni Heynemann
  • Limax hyperboreus Westerleund
  • Limax ingersolli A. Binney
  • Limax laevis Muller
  • Limax montanus Ingersoll
  • Limax nicensis Bourguignat
  • Limax norvegicus Westerlund
  • Limax pallidus Schrenk
  • Limax parvulus Normand
  • Limax veranyanus Bourguignat
  • Limax weinlandi Heynemann

International Common Names

  • English: brown slug; marsh slug; smooth slug
  • Spanish: babosa; babosa gris chica
  • French: limace champêtre

Local Common Names

  • Brazil: lesma
  • Germany: Wasser-Egelschnecke

Summary of Invasiveness

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D. laeve is native to the Palaearctic and to at least the western half of the Nearctic. This species is frequently confused with other species in the genus Deroceras, in particular D. invadens. As a result the exact distribution of this species is uncertain. There is reliable evidence for its invasiveness in many other parts of the world. It is widespread in mountainous regions of South America where it is unlikely to be native (Hausdorf, 2002), although has been present for a long time, at least since the late nineteenth century (Simroth, 1910). It is also present in the Pacific islands, Australia and New Zealand. This species has a number of important survival strategies such as significant freeze tolerance and a well-developed anaerobic metabolism which allows it to stay underwater for days. In Hawaii it is believed to have a negative impact on a critically endangered species, Alsinidendron obovatum.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Mollusca
  •             Class: Gastropoda
  •                 Subclass: Pulmonata
  •                     Order: Stylommatophora
  •                         Suborder: Sigmurethra
  •                             Unknown: Limacoidea
  •                                 Family: Limacidae
  •                                     Genus: Deroceras
  •                                         Species: Deroceras laeve

Notes on Taxonomy and Nomenclature

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Deroceras is a large genus of terrestrial pulmonate slugs with at least 123 species (Wiktor, 2000). D. laeve is the most widespread taxon and has a large number of synonyms with 20 specific names listed by Kennard and Woodward (1926) and 21 by Wiktor (2000). This is mainly reflective of the variability of the species in body size, colouration and degree of development of the male copulatory organs and of its very wide distribution.

In North America this inherent variability has led to the recognition of allied but separate species by Pilsbry (1948). D. monentolophus Pilsbry has subsequently been synonymised with D. laeve by Wiktor (2000) who also expressed doubt about the specific distinctness of D. hesperium Pilsbry. Recently acquired molecular data on D. hesperium has led to the conclusion that this is not a separate species either and should now be reduced to synonymy with D. laeve (Roth et al., 2013).

Rowson et al. (2014b) when examining British Deroceras at the molecular level concluded that the greenhouse form of D. laeve is specifically distinct. This is important as the greenhouse form is readily transported with horticultural materials and is probably widely spread in artificial environments across the world. They also posited a genetically distinct form of laeve from wetlands in Ireland but this hypothesis needs to be more widely tested.

Essentially, the nomenclature of this species is well documented (Kennard and Woodward, 1926; Wiktor, 2000) and the taxonomy is clear. Confusion, however, has arisen in the conflation of D. laeve with other invasive Deroceras species and particularly with D. invadens (Reise et al., 2011; Hutchinson et al., 2014). D. invadens is genetically and physically distinct from D.laeve but many workers in South America, Australia and the USA have in the past, failed to distinguish it from D. laeve (Hutchinson et al., 2014). This has probably distorted our understanding of the distribution, behaviour and agronomy of the species as reported in the literature and should be borne in mind when viewing this datasheet.

Description

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D. laeve is a small slug usually less than 22 mm long and sometimes much less. However, specimens from North America may be larger than 25 mm and overlap in size with the generally larger D. invadens. The body is cylindrical and somewhat broader distally. The mantle is unusually large in proportion and has delicate wrinkles visible in front, in live specimens. The tail section of the body is shorter than the mantle section. The back either slopes evenly towards the tail or is squared off and moderately truncate. A small keel is present close to the tail (Rowson et al., 2014a). 

It is variable in ground colour, ranging from an opaque chestnut- through grayish-brown to chocolate-brown. On close examination the back is seen to be sparsely mottled a darker shade, which is not easily visible to the naked eye. The mantle is similarly, or perhaps more densely, spotted. The sole is the same shade as the upper surface and the respiratory pore is only slightly paler than the rest of the body but individuals with more conspicuously pale-rimmed pores are reported from North America. Pedal and body mucus is colourless.

D. laeve is peculiar in having a partial or entire reduction of the male copulatory organs in most specimens (aphallic condition). Specimens with a fully developed penis (euphallic) are rare or absent in many populations but where euphally occurs the penis is elongate and spirally twisted (Rowson et al., 2014a). The distal intestine lacks a caecum (Wiktor, 2000).

Eggs - 1.8 x 1.5 to 2 x 1.3 mm; translucent, with calcareous particles (Quick, 1960).

Distribution

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The original native range of D. laeve is considered to be the Palaearctic and parts of the Nearctic (Wiktor, 2000). This species was accidentally introduced into new areas where it reached mountainous regions of the Neotropics quite early (nineteenth century). It later became established in non-mountainous parts of some South American countries, Australia, New Zealand and a range of Pacific Islands.

This species effectively now occurs on all continents except the Antarctic. Confusion with other species such as D. invadens, partly obscures understanding of its distribution outside the native range.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

ChinaWidespreadNative Not invasive Wiktor et al., 2000
PakistanPresent, few occurrencesNative Not invasive Hlavac, 2004Duikar village, Gilgit District, Karakorum
TaiwanPresent, few occurrencesNative Not invasive Tsai and Wu, 2008

Africa

Cape VerdePresentIntroduced Invasive Hutchinson et al., 2014
Sao Tome and PrincipePresentIntroduced Invasive Hutchinson et al., 2014
Spain
-Canary IslandsPresentNative Not invasive Fauna Europea, 2015

North America

BermudaPresentIntroduced Invasive Hutchinson et al., 2014
CanadaPresentPresent based on regional distribution.
-AlbertaPresentNative Invasive Lepitzki, 2001South west of Calgary, north to Lake Louise and Jasper, east to Edmonton and north to Slave Lake
-British ColumbiaPresentNative Not invasive Forsyth, 2005Upper Fraser Basin
-ManitobaPresentNative Not invasive Prystupa et al., 1987Agricultural pest in strawberry cultivation
-New BrunswickPresentNative Not invasive White-McLean and Redford, 2011
-Newfoundland and LabradorPresentNative Not invasive White-McLean and Redford, 2011
-Northwest TerritoriesPresentNative Not invasive White-McLean and Redford, 2011
-Nova ScotiaPresentNative Not invasive White-McLean and Redford, 2011
-OntarioPresentNative Not invasive White-McLean and Redford, 2011
-QuebecPresentNative Not invasive White-McLean and Redford, 2011
MexicoPresent, few occurrencesNative Not invasive White-McLean and Redford, 2011
USAPresentPresent based on regional distribution.
-AlabamaPresentNative Not invasive White-McLean and Redford, 2011
-AlaskaWidespreadNative Not invasive Roth and Lindberg, 1981; White-McLean and Redford, 2011Recorded in 14 counties
-ArkansasPresentNative Not invasive White-McLean and Redford, 2011
-CaliforniaPresentNative Not invasive White-McLean and Redford, 2011
-ColoradoPresentNative Not invasive Cockerell, 1927
-DelawarePresentNative Not invasive White-McLean and Redford, 2011
-FloridaPresentNative Not invasive White-McLean and Redford, 2011
-GeorgiaPresentNative Not invasive White-McLean and Redford, 2011
-HawaiiPresentIntroduced Invasive Cowie, 1997
-IdahoPresentNative Not invasive White-McLean and Redford, 2011
-IllinoisPresentNative Not invasive White-McLean and Redford, 2011
-IndianaPresentNative Not invasive White-McLean and Redford, 2011
-IowaPresentNative Not invasive White-McLean and Redford, 2011
-KansasPresentNative Not invasive White-McLean and Redford, 2011
-KentuckyPresentNative Not invasive White-McLean and Redford, 2011
-LouisianaPresentNative Not invasive White-McLean and Redford, 2011
-MainePresentNative Not invasive White-McLean and Redford, 2011
-MarylandPresentNative Not invasive White-McLean and Redford, 2011
-MichiganPresentNative Not invasive Forsyth, 2005; White-McLean and Redford, 2011
-MississippiPresentNative Not invasive White-McLean and Redford, 2011
-MissouriPresentNative Not invasive White-McLean and Redford, 2011
-NebraskaPresentNative Not invasive White-McLean and Redford, 2011
-New JerseyPresentNative Not invasive White-McLean and Redford, 2011
-New MexicoPresentNative Not invasive White-McLean and Redford, 2011
-New YorkPresentNative Not invasive White-McLean and Redford, 2011
-North CarolinaPresentNative Not invasive White-McLean and Redford, 2011
-North DakotaPresentNative Not invasive White-McLean and Redford, 2011
-OhioPresentNative Not invasive White-McLean and Redford, 2011
-OklahomaPresentNative Not invasive White-McLean and Redford, 2011
-PennsylvaniaPresentNative Not invasive White-McLean and Redford, 2011
-South DakotaPresentNative Not invasive White-McLean and Redford, 2011
-TennesseePresentNative Not invasive White-McLean and Redford, 2011
-TexasPresentNative Not invasive White-McLean and Redford, 2011
-UtahPresentNative Not invasive White-McLean and Redford, 2011
-VermontPresentNative Not invasive White-McLean and Redford, 2011
-VirginiaPresentNative Not invasive White-McLean and Redford, 2011
-WashingtonPresentNative Not invasive White-McLean and Redford, 2011
-West VirginiaPresentNative Not invasive White-McLean and Redford, 2011
-WisconsinPresentNative Not invasive White-McLean and Redford, 2011

Central America and Caribbean

Costa RicaPresentIntroduced Invasive Hutchinson et al., 2014
DominicaPresentIntroduced Invasive Robinson et al., 2009
JamaicaPresentIntroducedWhite-McLean and Redford, 2011

South America

ArgentinaPresentIntroduced Invasive Martín et al., 2009Reserva de Usos Múltiples Isla Martin Garcia, Rio de la Plata superior
BrazilPresentIntroduced Invasive Maurer et al., 2002
-Santa CatarinaPresentIntroduced Invasive Maurer et al., 2002Agricultural pest
ChilePresentIntroduced1985Araya, 2015
-Easter IslandPresentIntroduced Invasive Hutchinson et al., 2014
ColombiaPresentIntroducedpre 1910 Invasive Simroth, 1910; Hausdorf, 2002
PeruPresentIntroduced Invasive Hutchinson et al., 2014
UruguayPresentIntroduced1963 Invasive Campos and Calvo, 2006
VenezuelaPresentIntroducedpre 1970 Invasive Fernandez de, 1982

Europe

AndorraPresentNative Not invasive Fauna Europea, 2015
AustriaPresentNative Not invasive Fauna Europea, 2015
BelarusPresentNative Not invasive Fauna Europea, 2015
BelgiumPresentNative Not invasive Fauna Europea, 2015
Bosnia-HercegovinaPresentNative Not invasive Fauna Europea, 2015
CroatiaPresentNative Not invasive Fauna Europea, 2015
Czech RepublicPresentNative Not invasive Fauna Europea, 2015
DenmarkPresentNative Not invasive Fauna Europea, 2015
EstoniaPresentNative Not invasive Fauna Europea, 2015
Faroe IslandsPresentNative Not invasive Fauna Europea, 2015
FinlandPresentNative Not invasive Fauna Europea, 2015
FrancePresentNative Not invasive Fauna Europea, 2015
-CorsicaPresentNative Not invasive Fauna Europea, 2015
GermanyPresentNative Not invasive Fauna Europea, 2015; Ludwig et al., 2015
HungaryPresentNative Not invasive Fauna Europea, 2015
IcelandPresentNative Not invasive Fauna Europea, 2015
IrelandPresentNative Not invasive Fauna Europea, 2015
ItalyPresentNative Not invasive Fauna Europea, 2015
LatviaPresentNative Not invasive Fauna Europea, 2015
LiechtensteinPresentNative Not invasive Fauna Europea, 2015
LithuaniaPresentNative Not invasive Fauna Europea, 2015
LuxembourgPresentNative Not invasive Fauna Europea, 2015
MacedoniaPresentNative Not invasive Fauna Europea, 2015
MoldovaPresentNative Not invasive Fauna Europea, 2015
MontenegroPresentNative Not invasive Fauna Europea, 2015
NetherlandsPresentNative Not invasive Fauna Europea, 2015
NorwayPresentNative Not invasive Fauna Europea, 2015
PolandPresentNative Not invasive Fauna Europea, 2015
PortugalPresentNative Not invasive Fauna Europea, 2015
-AzoresPresentNativeBackhuys, 1975
-MadeiraPresentNative Not invasive Fauna Europea, 2015
RomaniaPresentNative Not invasive Fauna Europea, 2015
Russian FederationPresentNative Not invasive Fauna Europea, 2015
-Central RussiaPresentNative Not invasive Fauna Europea, 2015
-Eastern SiberiaPresentNative Not invasive Fauna Europea, 2015
-Northern RussiaPresentNative Not invasive Fauna Europea, 2015
-Russian Far EastPresentNative Not invasive Fauna Europea, 2015
-Southern RussiaPresentNative Not invasive Fauna Europea, 2015
-Western SiberiaPresentNative Not invasive Fauna Europea, 2015
SerbiaPresentNative Not invasive Fauna Europea, 2015
SlovakiaPresentNative Not invasive Fauna Europea, 2015
SloveniaPresentNative Not invasive Fauna Europea, 2015
SpainPresentNative Not invasive Castillejo, 1997; Fauna Europea, 2015
-Balearic IslandsPresentNative Not invasive Fauna Europea, 2015
SwedenPresentNative Not invasive Fauna Europea, 2015
SwitzerlandPresentNative Not invasive Fauna Europea, 2015
UKWidespreadNative Not invasive Fauna Europea, 2015
-Channel IslandsPresentNative Not invasive Fauna Europea, 2015
UkrainePresentNative Not invasive Fauna Europea, 2015
Yugoslavia (former)PresentNative Not invasive Fauna Europea, 2015
Yugoslavia (Serbia and Montenegro)PresentNative Not invasive Fauna Europea, 2015

Oceania

American SamoaPresentIntroduced Invasive Hutchinson et al., 2014
FijiPresentIntroduced Invasive Hutchinson et al., 2014
New ZealandPresentIntroduced Invasive Barker, 2004; White-McLean and Redford, 2011
Norfolk IslandPresentIntroduced Invasive Hutchinson et al., 2014
Papua New GuineaPresentIntroduced Invasive Wiktor, 2000; AnimalBase, 2015
Pitcairn IslandPresentIntroduced Invasive Hutchinson et al., 2014
TongaPresentIntroduced Invasive Hutchinson et al., 2014

History of Introduction and Spread

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Very little is known about means, rate of travel and date of transfer of D. laeve into new territories. The greenhouse form of D. laeve recognised in Britain and Ireland (Rowson et al., 2014a; Rowson et al., 2014b) may have been accidentally introduced into new areas with horticultural produce. The transfer of D. laeve with agricultural materials of both forms is also possible but undocumented.

In 1897, D. laeve was first recorded in Hawaii (Cowie, 1997). Today it is believed that it is likely to be present on all of the main islands such as Lanai, Kauai, Oahu and Maui.

In South America, D. laeve was is believed to have been introduced by the agricultural trade and was recorded in Colombia before 1910, Uruguay in 1963, Chile in 1985 and Veneuzela before 1970 (de Fernandez, 1982; Cowie, 1997; Campos and Calov, 2006l; Araya, 2015).

In 2001, D. laeve was found in Duikar village, Gilgit District, northern Pakistan. This new record, the highest located in Karakoram, is believed to be an extension of its continuous distribution in the mid-Hunza river region (Hlavac, 2004).

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Chile 1985 Crop production (pathway cause) Yes Araya (2015)
Colombia Pre 1910 Crop production (pathway cause) Yes Cowie (1997)
Hawaii 1897 Yes Cowie (1997)
Uruguay 1963 Crop production (pathway cause) Yes Campos and Calvo (2006)
Venezuela Pre 1970 Crop production (pathway cause) Yes Fernandez de (1982)

Risk of Introduction

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Due to the fact that D. laeve is present on all continents, except Antarctica, it is likely that the risk of this species being introduced into new areas is high. This is likely to occur accidentally with plants, good or waste including agricultural or garden waste (Thomas et al., 2010).

Habitat

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D. laeve is partially amphibious and is present across a large range of habitats. These include moist habitats such as wet marshes, wet woodlands, fields, river banks and meadows and it can sometimes be found in greenhouses and as a garden pest (White-McLean and Redford, 2011). It is typically found from sea level to altitudes of greater than 4,800 m. In its native range, D. laeve takes refuge under leaf litter and woody debris (Thomas et al., 2010).

Habitat List

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CategoryHabitatPresenceStatus
Terrestrial-managed
Cultivated / agricultural land Secondary/tolerated habitat Harmful (pest or invasive)
Cultivated / agricultural land Secondary/tolerated habitat Natural
Managed forests, plantations and orchards Secondary/tolerated habitat Natural
Protected agriculture (e.g. glasshouse production) Secondary/tolerated habitat Harmful (pest or invasive)
Terrestrial-natural
semi-natural/Cold lands / tundra Secondary/tolerated habitat Natural
semi-natural/Natural forests Secondary/tolerated habitat Natural
semi-natural/Natural grasslands Secondary/tolerated habitat Natural
semi-natural/Riverbanks Secondary/tolerated habitat Natural
semi-natural/Wetlands Secondary/tolerated habitat Natural

Hosts/Species Affected

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A wide range of plants are consumed by D. laeve including Fittonia, Datura stramonium and species of Lilium, Iris, Narcissus, Chrysanthemum, Fragaria and Cyclamen (Getz, 1959). In China D. laeve has been observed to feed on broad beans (Vicia faba) and species of Brassica in rural villages (Wiktor et al., 2000), in Canada on strawberries (Fragaria × ananassa) in farms (Prystupa et al., 1987) and in the USA on weeds and some crops in no-tillage cropping systems (Rogers et al., 1985). Its wild food has not been studied fully but probably includes both live and dead green plants in the habitats it frequents (Wiktor, 2000).

Host Plants and Other Plants Affected

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Plant nameFamilyContext
Asparagus officinalis subsp. officinalisLiliaceaeMain
Brassica spp.BrassicaceaeMain
Chrysanthemum (daisy)AsteraceaeMain
Cucurbita maxima (giant pumpkin)CucurbitaceaeMain
Cucurbita pepo (marrow)CucurbitaceaeMain
CyclamenPrimulaceaeMain
Datura stramonium (jimsonweed)SolanaceaeMain
Daucus carota (carrot)ApiaceaeMain
FittoniaAcanthaceaeMain
Fragaria (strawberry)RosaceaeMain
Fragaria vesca (wild strawberry)RosaceaeMain
Iris (irises)IridaceaeMain
Lactuca sativa (lettuce)AsteraceaeMain
Lilium (lily)LiliaceaeMain
Narcissus (daffodil)LiliaceaeMain
Vicia faba (faba bean)FabaceaeMain

Growth Stages

Top of page Flowering stage, Fruiting stage, Post-harvest, Seedling stage, Vegetative growing stage

List of Symptoms/Signs

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SignLife StagesType
Fruit / external feeding
Growing point / external feeding
Inflorescence / external feeding
Leaves / external feeding
Leaves / frass visible
Leaves / shredding
Seeds / external feeding
Stems / external feeding
Vegetative organs / external feeding
Whole plant / external feeding
Whole plant / frass visible

Biology and Ecology

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Reproductive Biology

D. laeve is an annual species and can grow rapidly to maturity in as little as a month (AnimalBase, 2015). It can potentially reproduce all year round (Jordaens et al., 2006). Although outcrossing has been recorded, many populations are aphallic and reproduce uniparentally. Eggs are laid singly or in small clusters, mainly in spring but probably at any time of year. They are large relative to the slug’s body size, at 2 x 1.5 mm and are translucent and finely punctuate, lacking a calcified shell (Quick, 1961).

Physiology and Phenology

This species lives in areas where it may be submerged frequently. As a result, it appears to be able to switch to anaerobiosis under water (Storey et al., 2007) and can survive immersion for days, as can its eggs. Juveniles can hatch under water and will migrate to the surface. As might be expected of a species which can live within the Arctic Circle, it has a wide temperature tolerance (0-30oC) and can survive freezing (Getz, 1959). A 100 fold increase in glucose levels have been recorded which are believed to provide a cryoprotective function during freezing (Storey et al., 2007).

D. laeve is a small, fast-moving and agile slug though not as irritable as D. invadens. Strikingly, it can continue to move flexibly under water and its pedal mucus does not seem to be easily washed off by immersion.

Longevity

Maximum life span is about one year but it can progress from egg to maturity in about one month.

Activity Patterns

D. laeve can reproduce at almost any time of year in the temperate zone and probably in other regions of the world (Rowson et al., 2014a).

Nutrition

D. laeve will feed on plant material and also carrion and live invertebrates (Herbert, 2010). Under laboratory conditions D. laeve may eat up to 40% of its total body weight per day (Osborne, 2015).

Environmental Requirements

Deroceras laeve has a wide temperature tolerance and can survive five hours at -8°C, although not at -10°C (Getz, 1959). It is very hygrophilous and usually found in the vicinity of water where other slugs tend not to occur but can enter damp woodlands and farmland under suitable conditions (Rowson et al., 2014a).

Climate

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ClimateStatusDescriptionRemark
C - Temperate/Mesothermal climate Tolerated Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C
Cf - Warm temperate climate, wet all year Tolerated Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Df - Continental climate, wet all year Preferred Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)
Ds - Continental climate with dry summer Tolerated Continental climate with dry summer (Warm average temp. > 10°C, coldest month < 0°C, dry summers)
ET - Tundra climate Tolerated Tundra climate (Average temp. of warmest month < 10°C and > 0°C)

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
65 35

Air Temperature

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Parameter Lower limit Upper limit
Absolute minimum temperature (ºC) -10
Mean annual temperature (ºC) 0 35
Mean maximum temperature of hottest month (ºC) 10 30
Mean minimum temperature of coldest month (ºC) -5 5

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Anas platyrhynchos Predator Adults/Juveniles not specific
Cychrus caraboides Predator Eggs/Juveniles not specific
Erinaceus europaeus Predator Adults not specific
Phasmarhabditis hermaphrodita Parasite Adults not specific Y
Silpha atrata Predator Adults/Juveniles not specific
Tetanocera elata Parasite
Tetanocera plebeja Predator not specific
Tetanocera valida Predator to genus

Notes on Natural Enemies

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Predators of D. laeve include a number of ground beetle species of the genera Carabus and Cychrus (for example Cychrus caraboides), silphid beetles such the European species Silpha atrata, and mammalian (Eurasian hedgehog, Erinaceus europaeus) and aquatic bird predators (Anas platyrhynchos). In addition, species of Sciomyzidae (marsh or snail-killing flies) may be important in controlling numbers in natural habitats of the Palaearctic and Nearctic. Larval sciomyzids actively predate, or more often, parasitise gastropods in aquatic or semi-aquatic habitats. For instance, Tetanocera plebeia and T. valida are host specific as newly hatched larvae, for D. laeve and D. reticulatum (Trelka and Foote, 1970). In Europe T. elata is a potential biocontrol agent for D. reticulatum (Hynes et al., 2014) but also parasitises D. laeve.

Means of Movement and Dispersal

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Natural Dispersal

D. laeve can be naturally dispersed over short distances by water and flooding events (AnimalBase, 2015).

Vector Transmission

Passive migration on birds or mammals has not been recorded but is certainly possible, as with all invertebrates sharing aquatic habitats with migratory birds.

Accidental Introduction

D. laeve may be accidentally introduced into new areas as a contaminant linked with the transport of food, consumed goods, or in garden waste.

Pathway Causes

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Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Plants or parts of plantsAgriculture and gardening Yes AnimalBase, 2015
WaterFlooding Yes AnimalBase, 2015

Impact Summary

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CategoryImpact
Economic/livelihood Negative
Environment (generally) Negative
Human health Negative

Economic Impact

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D. laeve can be a serious pest of greenhouses (Animalbase, 2015), feeding on both living and dead plant material (Wiktor, 2000). This species may also impact some no-tillage agricultural systems in the USA (Rogers et al., 1985). Estimates of economic losses due to this species have not been calculated.

Environmental Impact

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Impact on Biodiversity

D. laeve sensu stricto is largely confined to habitats not occupied by many other slugs and rarely achieves population densities sufficient to impact natural plant communities. It may, however, have an impact on threatened plant species in vulnerable ecosystems (Joe and Daehler, 2008). There is some evidence indicating that D. laeve is impacting on the critically endangered Alsinidendron obovatum in Hawaii and also on Cyanea superba (Joe and Daehler, 2008).

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Alsinidendron obovatumCR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered)HawaiiJoe and Daehler, 2008
Cyanea superbaEW (IUCN red list: Extinct in the wild) EW (IUCN red list: Extinct in the wild)Joe and Daehler, 2008

Social Impact

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D. laeve is known as a host for a number of nematodes. These include Angiostrongylus costaricensis, which may infect humans if inadvertently ingested with vegetable crops in areas such as Brazil (Maurer et al., 2002), A. vasorum, a cardiopulmonary parasite in dogs and usually fatal (Nabais, 2012) and A. cantonensis, which has been reported to cause of eosinophilic meningoencephalitis in south-east Asia and the Pacific Islands (Wallace and Rosen, 1969).

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Tolerant of shade
  • Capable of securing and ingesting a wide range of food
  • Fast growing
  • Has high reproductive potential
  • Reproduces asexually
  • Has high genetic variability
Impact outcomes
  • Changed gene pool/ selective loss of genotypes
  • Negatively impacts agriculture
  • Negatively impacts human health
  • Negatively impacts animal health
  • Negatively impacts livelihoods
  • Threat to/ loss of native species
Impact mechanisms
  • Competition - monopolizing resources
  • Pest and disease transmission
  • Herbivory/grazing/browsing
  • Interaction with other invasive species
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult to identify/detect in the field
  • Difficult/costly to control

Uses

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D. laeve can be used in the laboratory as a research model.

Uses List

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General

  • Laboratory use
  • Research model

Similarities to Other Species/Conditions

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Other species with which D. laeve has undoubtedly been confused in the past include D. invadens and perhaps D. panormitanum sensu stricto, but to a much less degree (Reise et al., 2011). It is generally assumed that the best distinguishing features from these species is their larger size (25-35 mm) and consistently white-rimmed respiratory orifice. However, in North America D. laeve is known to grow larger than in Europe (also true of other warm countries) and specimens with white-rimmed respiratory orifices are not unknown (Hutchinson et al., 2014). The only safe way of distinguishing the native D.laeve in the USA (and elsewhere) is by dissection.

Little is known of a genetically distinct "greenhouse" form of D. laeve which, while larger and possibly differing in colour from the nominotypical form (Rowson et al., 2014b), has not yet been reliably identified outside Britain and Ireland.

Prevention and Control

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Control

Biological Control

Phasmarhabditis hermaphrodita is a nematode parasite of slugs which, though most effective in controlling D. reticulatum can also kill other species of Deroceras (Speiser et al., 2001). However, this form of control is uneconomic for field crops at present.

Chemical Control

Formulations of copper, metaldehyde and methiocarb were assessed for their efficacy in controlling D. laeve. Prystuppa et al. (1987) found that 2% methiocarb was the most effective treatment with copper failing to provide significant mortalities. It has been suggested that when applied at high concentrations, metaldehyde may act as a repellant to D. laeve and it has been suggested the efficacy of carbamates would be increased if slugs can get to water after treatment (Osborne, 2015).

Gaps in Knowledge/Research Needs

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Although D. laeve has been introduced into nearly all regions in the world, there is no clear information on the pathways of dispersal. Studies in this area would be relevant to interrupt transit and prevent new introductions. In addition to this, further studies are required to determine population numbers of this species in its native range as it is believed that they are declining as a result of construction and subsequent habitat destruction (AnimalBase, 2015).

References

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AnimalBase, 2015. AnimalBase. Göttingen, Germany: University of Göttingen. http://www.animalbase.org/

Araya JF, 2015. Current status of the non-indigenous molluscs in Chile, with the first record of Otala punctata (Müller, 1774) (Gastropoda: Helicidae) in the country and new records for Cornu aspersum (Müller, 1774) and Deroceras laeve (Müller, 1774). Journal of Natural History, 49(29/30):1731-1761. http://www.tandfonline.com/loi/tnah20

Backhuys W, 1975. Land and freshwater molluscs of the Azores. Amsterdam, Netherlands: Backhuys and Meesters.

Balashov I; Gural-Sverlova N, 2012. An annotated checklist of the terrestrial molluscs of Ukraine. Journal of Conchology, 41(1):91-109.

Barker GM, 2004. Natural enemies of terrestrial molluscs [ed. by Barker, G. M.]. Wallingford, UK: CABI Publishing, x + 644 pp. http://www.cabi.org/CABeBooks/default.aspx?site=107&page=45&LoadModule=PDFHier&BookID=209

Campos J; Calvo A, 2006. [English title not available]. (Moluscos introducidos en Uruguay.) Comunicaciones de la Sociedad Malacológica del Uruguay, 9(89):75-78.

Castillejo J, 1997. [English title not available]. (Babosas del Noroeste Ibérico) . Santiago, Spain: Universidad de Santiago de Compostela.

Cockerell TDA, 1927. Zoology of Colorado. Denver, Colorado, USA: Welch-Haffner Printing, 262 pp.

Cowie RH, 1997. Catalog and bibliography of the nonindigenous nonmarine snails and slugs of the Hawaiian Islands. Bishop Museum Occasional Papers, No. 50. 1-66.

Fauna Europea, 2015. Fauna Europea database. European Commission. http://www.faunaeur.org/

Fernandez VJ de, 1982. A study on slugs damaging crops in Venezuela. (Contribucion al conocimiento de las babosas y sietecueros (mollusca: gastropoda) que causan danos a la agricultura en Venezuela.) Revista de la Facultad de Agronomia - Universidad Central (Venezuela) 1982, 12(3/4):353-386.

Forsyth RG, 2005. Terrestrial gastropods of the upper Fraser basin of British Columbia. Victoria, British Columbia, Canada: Royal British Columbia Museum, 26 pp.

Getz LL, 1959. Notes on the ecology of slugs: Arion circumscriptus, Deroceras reticulatum, and D. laeve. The American Midland Naturalist, 61:485-498.

Hausdorf B, 2002. Introduced land snails and slugs in Colombia. Journal of Molluscan Studies, 68:127-131.

Herbert DG, 2010. The introduced terrestrial mollusca of South Africa [ed. by Herbert, D. G.]. Pretoria, South Africa: South African National Biodiversity Institute, vi + 108 pp.

Hlavac JC, 2004. A new record of Deroceras laeve (O. Müller, 1774) from Pakistan (gastropoda: pulmonata: agriolimacidae). Folia Malacologica, 12(4):181-182.

Horsak M; Dvorak L; Jurickova L, 2004. Greenhouse gastropods of the Czech Republic: current stage of research. Malacological Newsletter, 22:141-147.

Hutchinson JMC; Reise H; Robinson DG, 2014. A biography of an invasive terrestrial slug: the spread, distribution and habitat of Deroceras invadens. NeoBiota, No.23:17-64. http://neobiota.pensoft.net/articles.php?id=4006

Hynes TM; Giordani I; Larkin M; McDonnell RJ; Gormally MJ, 2014. Larval feeding behaviour of Tetanocera elata (Diptera: Sciomyzidae): potential biocontrol agent of pestiferous slugs. Biocontrol Science and Technology, 24(9):1077-1082. http://www.tandfonline.com/loi/cbst20

Joe SM; Daehler CC, 2008. Invasive slugs as under-appreciated obstacles to rare plant restoration: evidence from the Hawaiian Islands. Biological Invasions, 10(2):245-255. http://www.springerlink.com/link.asp?id=103794

Jordaens K; Dongen Svan; Temmerman K; Backeljau T, 2006. Resource allocation in a simultaneously hermaphroditic slug with phally polymorphism. Evolutionary Ecology, 20(6):535-548. http://springerlink.metapress.com/link.asp?id=100160

Kennard AS; Woodward BB, 1926. Synonymy of the British non-marine Mollusca (Recent and post-Tertiary). London, UK: British Museum (Natural History), xxiv + 447 pp.

Lepitzki DAW, 2001. Gastropods: 2000 preliminary status ranks for Alberta. Unpublished report prepared for Alberta Sustainable Resource Development, Fish and Wildlife Division. Edmonton, Alberta, Canada 126 pp.

Ludwig A; Reise H; Hutchinson JMC, 2015. The slug fauna of gardens in the town of Görlitz (Saxony, Germany). (Die Nacktschneckenfauna in Gärten der Stadt Görlitz (Sachsen, Deutschland).) Berichte der Naturforschenden Gesellschaft der Oberlausitz, 23:43-57. http://www.naturforschende-gesellschaft-der-oberlausitz.de/Publikationen

Martín SM; César II; Liberto R, 2009. Distribution of Deroceras reticulatum (Müller, 1774) (Pulmonata Stylommatophora) in Argentina with first record of the Reserva de Usos Múltiples Isla Martin Garcia, Río de la Plata superior. Brazilian Journal of Biology, 69(4):1115-1119. http://www.bjb.com.br

Maurer RL; Graeff-Teixeira C; Thomé JW; Chiaradia LA; Sugaya H; Yoshimura K, 2002. Natural infection of Deroceras laeve (Mollusca: Gastropoda) with metastrongylid larvae in a transmission focus of abdominal angiostrongyliasis. Revista do Instituto de Medicina Tropical de São Paulo, 44(1):53-54.

Nabais JNP, 2012. Aelurostrongylus abstrusus and Angiostrongylus vasorum (nematoda: angiostrongylidae) infection in cats and dogs in the district of Lisbon, Portugal. (Infecção por Aelurostrongylus abstrusus e Angiostrongylus vasorum (Nematoda: Angiostrongylidae), em gatos e cães no distrito de Lisboa, Portugal.) Dissertação de Mestrado Integrado em Medicina Veterinária. Lisbon, Portugal: Universidade Técnica de Lisboa, 80 pp.

NOBANIS, 2006. Online Database of the North European and Baltic Network on Invasive Alien Species (NOBANIS). Online Database of the North European and Baltic Network on Invasive Alien Species (NOBANIS). http://www.nobanis.org

Osborne LS, 2015. Deroceras slugs. North Carolina, USA: North Carolina State University. http://ipm.ncsu.edu/AG136/slug3.html

Prystupa BD; Holliday NJ; Webster GRB, 1987. Molluscicide efficacy against the marsh slug, Deroceras laeve (Stylommatophora: Limacidae), on strawberries in Manitoba. Journal of Economic Entomology, 80(4):936-943.

Quick HE, 1960. British slugs (Pulmonata: Testacellidae, Arionidae, Limacidae). Bulletin of the British Museum (Natural History) Zoology, 6:1-226.

Reise H; Hutchinson JMC; Schunack S; Schlitt B, 2011. Deroceras panormitanum and congeners from Malta and Sicily, with a redescription of the widespread pest slug as Deroceras invadens N. sp. Folia Malacologica, 19(4):201-223. http://versita.metapress.com/link.asp?target=contribution&id=E8257X5567027763

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Roth B; Lindberg DR, 1981. Terrestrial mollusks of Attu, Aleutian Islands, Alaska. Arctic, 34(1):43-47.

Rowson B; Anderson R; Turner JA; Symondson WOC, 2014. The slugs of Britain and Ireland: undetected and undescribed species increase a well-studied, economically important fauna by more than 20%. PLoS ONE, 9:e91907.

Rowson B; Turner J; Anderson R; Symondson W, 2014. Slugs of Britain and Ireland: identification, understanding and control. Telford, UK: Field Studies Council, 136 pp.

Schileyko A; Sysoev A, 2009. Land snails and slugs of Russia and adjacent countries. Sofia-Moscow, Bulgaria, Russia: Pensoft, 312 pp.

Simroth H, 1910. [English title not available]. (Nacktschneckenstudien in den Sudalpen.) Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft, 32:275-348.

Storey KB; Storey JM; Churchill TA, 2007. Freezing and anoxia tolerance of slugs: a metabolic perspective. Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology, 177(8):833-840. http://www.springerlink.com/content/mg0l5021041h7554/?p=27d9e75e744647b18158a7224d5a28a9&pi=0

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Wiktor A, 2000. Agriolimacidae (Gastropoda: Pulmonata) - a systematic monograph. Annales Zoologici, 49(4):347-590.

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Contributors

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23/11/15 Original text by:

Roy Anderson, Consultant, Northern Ireland

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