Deroceras laeve
(meadow slug)

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

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

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.

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).

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).

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.

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.

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).

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).

• 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

• 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

• Competition - monopolizing resources
• Pest and disease transmission
• Herbivory/grazing/browsing
• Interaction with other invasive species

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect in the field
• Difficult/costly to control

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