Discus rotundatus (rotund disc)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Biology and Ecology
- Latitude/Altitude Ranges
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Plant Trade
- Impact Summary
- Impact: Economic
- Impact: Environmental
- Risk and Impact Factors
- Detection and Inspection
- Prevention and Control
- Links to Websites
- Distribution Maps
Don't need the entire report?
Generate a print friendly version containing only the sections you need.Generate report
PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Discus rotundatus (O. F. Müller, 1774)
Preferred Common Name
- rotund disc
Other Scientific Names
- Goniodiscus rotundatus Müller, 1774
- Gonyodiscus abietinus Bourguignat, 1864
- Gonyodiscus azorica Mousson, 1858
- Gonyodiscus brocchii Calcara, 1845
- Gonyodiscus machadoi Milne-Edwards, 1885
- Gonyodiscus megerlei Mabille, 1865
- Gonyodiscus radiatus Da Costa, 1778
- Gonyodiscus rotundatus Müller, 1774
- Gonyodiscus spelaeus Kobelt, 1907
- Gonyodiscus supracostatus von Sandberger, 1874
- Helix abietina Bourguignat, 1864
- Helix machadoi Milne-Edwards, 1885
- Helix rotundatus Müller, 1774
- Patula azorica Mousson, 1858
- Patula rotundata Müller, 1774
International Common Names
- English: garden disc snail; rotund disc snail; rounded snail
- French: bouton commun
Local Common Names
- Austria: gefleckte diskusschnecke; gefleckte knopfschnecke; gefleckte schüsselschnecke
- Croatia: sareni dugmetac
- Germany: gefleckte diskusschnecke; gefleckte knopfschnecke; gefleckte schüsselschnecke
Summary of InvasivenessTop of page
Discus rotundatus, commonly known as rotund disc, is a small snail with a flattened disc-shaped shell. It one of the most widespread and common snails throughout large parts of Europe. It is frequently introduced to other countries and has become established in North America, South Africa, New Zealand and Brazil. In most cases of establishment outside its natural range populations remain restricted to confined colonies. It inhabits a wide range of habitats, including sheltered places in forest and urban areas but also some moist and shady open habitats. Due to a slow rate of dispersal, the species displays overall only a low degree of invasiveness. It is a vector of tobacco mosaic virus although this has not so far been reported to be of significant economic importance.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Mollusca
- Class: Gastropoda
- Subclass: Pulmonata
- Order: Stylommatophora
- Suborder: Sigmurethra
- Unknown: Arionoidea
- Family: Endodontidae
- Genus: Discus
- Species: Discus rotundatus
Notes on Taxonomy and NomenclatureTop of page
Discus rotundatus (Müller, 1774) belongs to the subgenus Gonyodiscus, which in some taxonomic revisions has been elevated to genus level. Therefore in some publications the species is referred to as Gonyodiscus rotundatus (Müller, 1774). Several subspecies have been described, with D. rotundatus rotundatus (Müller, 1774) being most widely distributed throughout its native range. The subspecies D. r. omalisma (Fagot, 1879) has been recorded from Spain and France. Discus r. abietina (Bourguignat, 1864) has been described from Algeria but its taxonomic significance remains disputed (Germain, 1930; Kuznik-Kowalska, 2008; Fauna Europaea, 2013).
DescriptionTop of page
D. rotundatus is approximately 2.5 mm in height and ranges in width from 5.5-7.2 mm (White-McLean, 2016). The flattened almost disc-shaped shell is yellowish brown with reddish brown spots or transverse strips at regular intervals. It is flat with 5.5-6 narrow and tightly coiled whorls, coarsely ribbed, and weakly keeled at the periphery. Albino shells are found occasionally. The umbilicus equals 1/3 of the shell diameter or more (Kerney et al., 1979; Welter-Schultes, 2013). In central Europe the animal is bluish on upper side, greyish white on foot below inferior tentacles; in southern Europe it is bluish black (Welter-Schultes, 2013;White-McLean, 2016).
DistributionTop of page
In its native range of west and central Europe, D. rotundatus is one of the commonest and most widespread snails, including in Ireland and Great Britain (National Museums Northern Ireland, 2010; Horsák et al., 2013; Welter-Schultes, 2013). Its native range stretches from Iceland and Ireland in the West towards the eastern Baltic region, Romania and the Ukraine in the East. In the North it inhabits southern Scandinavia and towards the South Portugal, Spain, Italy and the northeastern states of Africa. There are no records of native occurrences in southeast Europe or from northeast Africa. Whether occasional records from its southeastern limits refer to natural occurrences or human-mediated introductions remains open to debate (Örstan, 2003; Štamol, 2010; Štamol et al., 2015).
Distribution TableTop of page
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/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Turkey||Present, few occurrences||Introduced||Örstan, 2003|
|Algeria||Present||Native||Not invasive||White-McLean, 2011|
|South Africa||Present, few occurrences||before 1986||Introduced||Herbert, 2010||East and West Cape|
|-Canary Islands||Present||Native||Not invasive||Fauna Europaea, 2013|
|Tunisia||Present||Native||Not invasive||Gireaud, 2007|
|Canada||Present||before 1953||Introduced||Grimm et al., 2016|
|-British Columbia||Present||before 1953||Introduced||Forsyth, 2004; Forsyth et al., 2016|
|-New Brunswick||Present||Introduced||Forsyth et al., 2016|
|-Newfoundland and Labrador||Present||Introduced||NatureServe, 2015; Forsyth et al., 2016|
|-Nova Scotia||Present||Introduced||NatureServe, 2015; Forsyth et al., 2016|
|-Ontario||Present||before 1953||Introduced||Forsyth et al., 2016; Grimm et al., 2016|
|-Quebec||Present||before 2008||Introduced||Örstan, 2012; Forsyth et al., 2016|
|USA||Present||1930s||Introduced||Pilsbry, 1948; Dundee, 1974|
|-California||Present||Introduced||Hertz, 1996; Roth and Sadeghian, 2006||San Diego|
|-District of Columbia||Present||Introduced||Steury and Steury, 2011|
|-New Jersey||Present||Introduced||NatureServe, 2015|
|-New York||Present||Introduced||Hotopp and Pearce, 2007|
|Brazil||Present||Introduced||Salvador et al., 2013||Trinidade Island|
|Andorra||Present||Native||Not invasive||Fauna Europaea, 2013|
|Austria||Present||Native||Not invasive||Kuznik-Kowalska, 1999|
|Belarus||Present||Native||Not invasive||Fauna Europaea, 2013|
|Belgium||Present||Native||Not invasive||Poppe and Poppe, 2016|
|Bulgaria||Present, few occurrences||Introduced||Georgiev, 2014|
|Croatia||Present, few occurrences||Not invasive||Štamol, 2010; Štamol et al., 2015|
|Czech Republic||Present||Native||Not invasive||Horsák et al., 2015|
|Czechoslovakia (former)||Present||Native||Not invasive||Horsák et al., 2015|
|Denmark||Present||Native||Not invasive||Fauna Europaea, 2013; Liggia, 2016|
|Estonia||Present||Native||Not invasive||Fauna Europaea, 2013|
|Finland||Present||Introduced||Kerney and Cameron, 1979|
|France||Present||Native||Not invasive||Germain, 1930|
|-Corsica||Present||Native||Not invasive||Réal and Réal-Testud, 1988|
|Germany||Present||Native||Not invasive||Fauna Europaea, 2013; Liggia, 2016|
|Hungary||Present||Native||Not invasive||Solymos, 2008|
|Iceland||Present||Native||Not invasive||Liggia, 2016|
|Ireland||Present||Native||Not invasive||Anderson, 2005|
|Italy||Present||Native||Not invasive||Manganelli et al., 1995; Reitano et al., 2012|
|Latvia||Present||Native||Not invasive||Fauna Europaea, 2013|
|Liechtenstein||Present||Native||Not invasive||Turner et al., 1998|
|Lithuania||Present||Native||Not invasive||Fauna Europaea, 2013|
|Luxembourg||Present||Native||Not invasive||Fauna Europaea, 2013|
|Malta||Present, few occurrences||Introduced||Giusti et al., 1995|
|Netherlands||Present||Native||Not invasive||Fauna Europaea, 2013; Liggia, 2016|
|Norway||Present||Native||Not invasive||Kuznik-Kowalska, 1999; Fauna Europaea, 2013|
|Poland||Present||Native||Not invasive||Kuznik-Kowalska, 1999|
|Portugal||Present||Native||Not invasive||Nobre, 1913; Nobre, 1941|
|-Azores||Present||Native||Not invasive||Fauna Europaea, 2013; Liggia, 2016|
|-Madeira||Restricted distribution||Introduced||Seddon, 2008||Anthropophilic|
|Romania||Present||Native||Not invasive||Fauna Europaea, 2013|
|Russian Federation||Present||Native||Not invasive||Liggia, 2016|
|-Western Siberia||Present||Native||Not invasive||Liggia, 2016|
|Slovakia||Present||Native||Not invasive||Horsák et al., 2015|
|Slovenia||Present||Native||Not invasive||Fauna Europaea, 2013|
|Spain||Present||Native||Not invasive||Fauna Europaea, 2013; Liggia, 2016|
|-Balearic Islands||Present||Not invasive||Altaba, 1996; Beckmann, 2007|
|Sweden||Present||Native||Not invasive||Fauna Europaea, 2013; Liggia, 2016|
|Switzerland||Present||Native||Not invasive||Turner et al., 1998|
|UK||Present||Native||Not invasive||Anderson, 2005|
|-Channel Islands||Present||Native||Not invasive||Fauna Europaea, 2013|
|Ukraine||Present||Native||Not invasive||Balashov and Gural-Sverlova, 2012|
|New Zealand||Present||Native||Not invasive||Liggia, 2016|
History of Introduction and SpreadTop of page
Risk of IntroductionTop of page
As a soil and leaf litter inhabiting snail, D. rotundatus can easily be accidently introduced via the horticultural and nursery trade. According to US national PPQ statistics the species accounted for 1.08% of all gastropod interception in the USA between 1993 and 1998 (Robinson, 1999). This indicates that risks of accidental introduction are highest when phytosanitary standards fail to intercept snails from shipments within the horticultural trade. There are no indications that the species has been deliberately introduced to new areas in the past.
HabitatTop of page
Originally a woodland species, D. rotundatus also invades anthropogenic habitats such as parks and ruins. It inhabits leaf-litter, being associated with rotting wood (Kuznik-Kowalska, 1999). In central and northwestern Europe, D. rotundatus primarily inhabits sheltered places in forests such as under dead wood logs and stones, litter and damp herbage. It also can be found in all kinds of moderately moist and shady places in open habitats and is often ubiquitous in hedgerows or any kind of man-altered terrain (Kerney et al., 1979; National Museums Northern Ireland, 2010; Welter-Schultes, 2013). The species is common in gardens, particularly among rubbish piles (Kerney et al., 1979; Welter-Schultes, 2013). In southern parts of its range it can be found under stones and disintegrating leaves in humid and shady habitats, in soil litter and at the basis of old walls, often in colonies of numerous individuals (Welter-Schultes, 2013). It is also an extremely common and widespread species in urban habitats in central Europe (Horsák et al., 2013).
In North America, it is largely found in gardens, parks and greenhouses (Herbert, 2010). In Western Cape, South Africa it has spread from suburban gardens into natural vegetation (shaded kloofs) in the Cape Peninsula National Park, whereas in the Eastern Cape it has been found in remote indigenous forests (Herbert, 2010).
Habitat ListTop of page
|Soil||Present, no further details||Natural|
|Terrestrial – Managed||Cultivated / agricultural land||Principal habitat||Natural|
|Protected agriculture (e.g. glasshouse production)||Secondary/tolerated habitat||Natural|
|Managed forests, plantations and orchards||Principal habitat||Natural|
|Urban / peri-urban areas||Principal habitat||Natural|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Principal habitat||Natural|
|Land caves||Present, no further details||Natural|
|Rocky areas / lava flows||Present, no further details||Natural|
Hosts/Species AffectedTop of page
D. rotundatus has not been reported as a pest of crops or other plants. It has, however, been listed as an important vector of the tobacco mosaic virus (Robinson, undated).
Biology and EcologyTop of page
In Europe, the reproductive season ranges from May to October and uniparental reproduction is regular (Kuznik-Kowalska, 1999; Welter-Schultes, 2013). On average eggs measure roughly 1 mm in diameter (ranging from 0.7-1.5 mm) and their size is positively correlated with the size of the parent (Frömming 1954; Kuznik-Kowalska, 1999). Eggs are deposited in clutches (1-15 eggs per clutch) with most often 3-4 eggs being arranged in a characteristic pyramid or in a row 2-3 weeks after copulation (Kuznik-Kowalska, 1999; Welter-Schultes, 2013). The eggs are laid in humid, sheltered places, preferably on a substratum that will later serve as a food source for the hatchlings, e.g. bits of bark, decaying wood or decaying leaves under trees (Kuznik-Kowalska, 1999; Welter-Schultes, 2013). The incubation period ranges from 10-36 days; juveniles hatch initially with 1.5-2.3 whorls, growing at a rate of 0.5 whorls per month. Maturity is reached in the second season at 5.5 whorls (Kuznik-Kowalska, 1999; Welter-Schultes, 2013).
D. rotundatus can reproduce by self-fertilization (R. Cameron, University of Sheffield, UK, personal communication, 2016).
More detailed information on the reproductive biology of D. rotundatus is provided by Kuznik-Kowalska (1999).
Population Size and Structure
In beech litter D. rotundatus was overserved to be among the dominant snail species reaching densities of > 13 individuals per m2, playing a prominent role with regards to litter ingestion (Mason, 1970). Densities vary between habitats and Kappes et al. (2009) demonstrated that in a wooded environment its density decreased with forest size.
D. rotundatus is primarily a litter feeder mainly ingesting plant debris, humus, algae and fungi. As such is one of the few land snails introduced to Canada not regarded a pest (Grimm et al., 2016). Egg cannibalism has been observed. Juveniles consumed conspecific eggs (both of their own clutch and of different clutches), but rejected eggs of other snail species, including other Discus spp. during multiple choice tests (Kuznik-Kowalska, 1999). There is little evidence that D. rotundatus is feeding extensively on eggs of other snail species (Kuznik-Kowalska, 1999).
D. rotundatus seems to compete with Discus ruderatus at higher altitutes and at the extreme north and east of its range, and the two species do rarely coexist (Welter-Schultes, 2013).
D. rotundatus is a west and central European species reaching 63°N latitude in Norway and 58°N in Sweden. It also inhabits countries with Mediterranean climate in southwest Europe and northeast Africa. The limitations to its climatic range towards southeast Europe are not clearly known, but it is absent from the Balkan and southern Carpathian countries (Kuznik-Kowalska, 1999).
Its upper altitudinal limits are given at 1,200 m a.s.l. in the Carpathians and Sudetes and 2,550 m a.s.l. in Switzerland (Germain, 1930; Kuznik-Kowalska, 1999). In France it has been recorded from 1,400 (rarely above 1,900) m a.s.l. in Savoie and 1,800-2,000 m a.s.l. in the Pyrenees (Germain, 1930).
D. rotundatus tolerates non-calcareous substrate but is usually rare on nutrient poor (dystrophic) soils and rocks, although it sometimes can be found in lagg woodland around the edges of raised bog and often on agriculturally enriched former peatlands (National Museums Northern Ireland, 2010; Welter-Schultes, 2013).
ClimateTop of page
|C - Temperate/Mesothermal climate||Preferred||Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C|
|Cf - Warm temperate climate, wet all year||Preferred||Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year|
|Cs - Warm temperate climate with dry summer||Preferred||Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers|
|Df - Continental climate, wet all year||Tolerated||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)|
Latitude/Altitude RangesTop of page
|Latitude North (°N)||Latitude South (°S)||Altitude Lower (m)||Altitude Upper (m)|
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
|Abax parallelepipedus||Predator||not specific||N|
|Columba oenas||Predator||not specific||N|
|Cosmocercoides dukae||Parasite||not specific||N|
|Erinaceus europaeus||Predator||not specific||N|
|Ficedula hypoleuca||Predator||not specific||N|
|Melinda caerula||Parasite||not specific||N|
|Myxophyllum steenstrupi||Parasite||not specific||N|
|Oxychilus helveticus||Predator||not specific||N|
|Parus major||Predator||not specific||N|
|Phasmarhabditis hermaphrodita||Parasite||not specific||N|
|Pherbellia albocostata||Parasite||not specific||N|
|Pherbellia dubia||Parasite||not specific||N|
|Platydemus manokwari||Predator||not specific||N|
|Sorex araneus||Predator||not specific||N|
|Sturnus vulgaris||Predator||not specific||N|
|Tetrahymena rostrata||Parasite||not specific||N|
|Turdus merula||Predator||not specific||N|
Notes on Natural EnemiesTop of page
Land snails have many natural predators, including mammals (e.g. hedgehogs or mice) and birds, thrushes in particular, also slow worms and toads. Invertebrate predators include other predatory snails, ground and rove beetles, centipedes, leeches, and flatworms. Also harvestmen of the family Ischyropsalidae are known to be specialised snail predators. However, there a few records of natural enemies referring directly to Discus or more specifically to D. rotundatus.
In Europe, predation of D. rotundatus has been recorded for a range of birds and mammals such as Columba oenas (stock dove), Ficedula hypoleuca (pied flycatcher), Parus major (great tit), Sturnus vulgaris (starling), Turdus merula (blackbird), Erinaceus europaeus (European hedgehog), and Sorex araneus (Eurasian shrew) (Allen, 2004).
The remains of Discus spp. were recorded amongst the gut contents of the ground beetle Abax parallelepipedus (Loreau, 1983), and in captivity D. rotundatus has been observed to be preyed upon by the land snail Oxychilus helveticus (Barker and Efford, 2004). Also in captivity, D. rotundatus is preyed upon by larvae of glow worms belonging to the beetle family Lampyridae (Tyler, 2016).
Parasitic Diptera, particularly of the family Sciomyzidae are frequently specialised to develop in gastropods. In Britain members of this family belonging to the genus Pherbellia (e.g. Pherbellia albocostata) have been recorded to parasitize Discus spp. and Pherbellia dubia specifically D. rotundatus (Bratt et al., 1969; Chandler, 1972; Revier, 1982). Equally, the parasitic fly Melinda caerula (Calliphoridae) is recorded to develop in D. rotundatus (Coupland and Barker, 2004).
In Australia, the flatworm Platydemus manokwari (Rhynchodemidae) preys on the genus Discus (Winsor et al., 2004).
Parasitic nematodes such as Cosmocercoides dukae or Rhabditis spp. have been recorded from the genus Discus (Morand et al., 2004), but only Phasmarhabditis hermaphrodita specifically from D. rotundatus (Morand et al., 2004). In France, infection rates of D. rotundatus by P. hermaphrodita can reach almost 40% (mean number per snail 0.5; ranging from 0-10) (Morand et al., 2004).
The ciliophoran parasites Tetrahymena rostrata and Myxophyllum steenstrupi have been recorded from D. rotundatus (Kazubski, 1958, 1959, 1978; Van As and Basson, 2004).
Means of Movement and DispersalTop of page
D. rotundatus moves actively only over very short distances and usually remains in confined colonies where it can become abundant (Grimm et al., 2016). It can, however, be easily passively transported over long distances and for this reason Robinson (1999) considered it a travelling species. Supporting the fact that this mode of dispersal is commonly taking place are records of snail interceptions at US ports between 1993-1998, when more than one percent of all specimens intercepted belonged to this species (Robinson, 1999),
D. rotundatus has been found in association with forestry enterprises in remote areas of Eastern Cape, South Africa. The most likely explanation for this is that the snails are present in sylviculture nurseries and that they were translocated to remote forestry plantations in the soil around sapling roots (Herbert, 2010). In cases where plantations are close to indigenous forests, native ecosystems are likely to be invaded by D. rotundatus in the long-term.
Pathway CausesTop of page
|Breeding and propagation||Sylviculture nurseries||Yes||Herbert, 2010|
|Cut flower trade||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Disturbance||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Escape from confinement or garden escape||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Flooding and other natural disasters||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes||Yes|
|Forestry||Sylviculture nurseries||Yes||Herbert, 2010|
|Hedges and windbreaks||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Hitchhiker||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Landscape improvement||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes||Yes|
|Nursery trade||Sylviculture nurseries||Yes||Herbert, 2010|
Pathway VectorsTop of page
|Aircraft||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Plants or parts of plants||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
|Soil, sand and gravel||Not explicitly mentioned in literature, but likely based on the species’ biology||Yes|
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Bark||adults; cysts; eggs; juveniles||Yes||Pest or symptoms usually visible to the naked eye|
|Bulbs/Tubers/Corms/Rhizomes||adults; cysts; eggs; juveniles||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Growing medium accompanying plants||adults; cysts; eggs; juveniles||Yes||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Roots||adults; cysts; eggs; juveniles||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Wood||adults; juveniles||Yes||Pest or symptoms usually visible to the naked eye|
|Plant parts not known to carry the pest in trade/transport|
|Stems (above ground)/Shoots/Trunks/Branches|
Impact SummaryTop of page
|Environment (generally)||Positive and negative|
Impact: EconomicTop of page
D. rotundatus (Müller) has been recorded as a vector of the tobacco mosaic virus (Robinson, undated; Heinze, 1958), and experiments have shown that when the virus is introduced to mouthparts of Discus snails it can be detected two days later in their digestive system (Borkakati et al., 2009). Details about this potential threat are not known, but it is thought that the economic importance of infection with tobacco mosaic virus through molluscs is small (Heinze, 1958).
Impact: EnvironmentalTop of page
Impact on Biodiversity
In the USA, D. rotundatus has been named as a potential threat to the endemic and endangered native Chittenango ovate amber snail (Novisuccinea chittenangoensis), of which only one extant population is known from Chittenango Falls, New York (Breisch and Niver, 2006; USFWS, 2006). However, there is currently no evidence for D. rotundatus impacting negatively on this species. Recent studies on the biology of D. rotundatus by Kuznik-Kowalska (1999) do not support the idea that the species poses a significant threat.
In Canada D. rotundatus is not regarded a pest as it feeds primarily on litter (Grimm et al., 2016).
Herbert et al. (2010) list the status of D. rotundatus in South Africa as "established, locally invasive" (p.5) but also describes its pest status as "probably a detritivore and of little pest significance" (p. 34).
Risk and Impact FactorsTop of page Invasiveness
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Is a habitat generalist
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Pioneering in disturbed areas
- Tolerant of shade
- Capable of securing and ingesting a wide range of food
- Benefits from human association (i.e. it is a human commensal)
Detection and InspectionTop of page
It is likely that the most common pathway of further spread of this species will be through shipments of ornamental plants, forest nursery stock and horticultural produce. Another possibility is the spread through shipments of tiles (Herbert, 2010). Whereas adult snails can readily be detected through standard phytosanitary inspection methods, small juvenile stages and eggs are much more difficult to detect.
Prevention and ControlTop of page
No specific measures for the control of D. rotundatus have been described.
No biological control agents have been assessed or used for the control of D. rotundatus. However, fly larvae belonging to the family of Sciomyzidae parasitize inside aquatic and terrestrial snails and slugs, which could turn individual species into potentially suitable control agents. This has been in particular discussed in the context of a possible control of schistosomiasis and other snail-borne diseases in Africa, South America and the Far East (Smith, 1989).
ReferencesTop of page
Allen JA, 2004. Avian and mammalian predators of terrestrial gastropods. In: Natural enemies of terrestrial molluscs [ed. by Barker GM]. Wallingford, UK: CABI Publishing, 1-36. http://www.cabi.org/CABeBooks/default.aspx?site=107&page=45&LoadModule=PDFHier&BookID=209
Altaba CR, 1996. Presence of Discus rotundatus (Gastropoda, Endodontidae) on the island of Mallorca. Miscellania Zoologica, 19(1):51-54.
As JGvan; Basson L, 2004. Ciliophoran (Ciliophora) parasites of terrestrial gastropods. In: Natural enemies of terrestrial molluscs [ed. by Barker GM]. Wallingford, UK: CABI Publishing, 559-578. http://www.cabi.org/cabebooks/ebook/20043115153
Balashov I; Gural-Sverlova N, 2012. An annotated checklist of the terrestrial molluscs of Ukraine. Journal of Conchology, 41(1):91-109.
Barker GM; Efford MG, 2004. Predatory gastropods as natural enemies of terrestrial gastropods and other invertebrates. In: Natural enemies of terrestrial molluscs [ed. by Barker GM]. Wallingford, UK: CABI Publishing, 279-403. http://www.cabi.org/CABeBooks/default.aspx?site=107&page=45&LoadModule=PDFHier&BookID=209
Beckmann KH, 2007. The land and freshwater molluscs of the Balearic Islands (Die Land- und Süsswassermollusken der Balearischen Inseln). Hackenheim, Germany: CochBooks, 155 pp.
BioLib, 2016. Rotund Disc - Discus rotundatus (O. F. Muller, 1774). http://www.biolib.cz/en/taxon/id2803/
Borkakati RN; Gogoi R; Borah BK, 2009. Snail from present perspective to the history of Assam. Asian Agri-History, 13(3):227-234.
Bratt AD; Knutson LV; Foote BA; Berg CO, 1969. Biology of Pherbellia (Diptera: Sciomyzidae). Memoir, Cornell University Agricultural Experiment Station, New York State College of Agriculture, Ithaca, New York, No. 404. 246 pp.
Breisch A; Niver R, 2006. Chittenango Ovate Amber Snail (Novisuccinea chittenangoensis) Recovery Plan, First Revision. Hadley, Massachusetts, USA: US Fish and Wildlife Service, 55pp. http://ecos.fws.gov/docs/recovery_plan/060823.pdf
CHANDLER PJ, 1972. The distribution of snail-killing flies (Diptera: Sciomy-zidae) in Ireland Northern Ireland and the Irish Republic. Proceedings and Transactions of the British Entomological and Natural History Society, 5(1):1-21.
Dundee D, 1974. Catalog of introduced molluscs of eastern North America (North of Mexico). Sterkiana, 55:1-37.
Fauna Europaea, 2013. Fauna Europeaea version 2.6.2. http://www.faunaeur.org/
Forsyth RG, 2004. Land Snails of British Columbia. Victoria, British Columbia, Canada: Royal British Columbia Museum, 188pp.
Forsyth RG; Maunder JE; McAlpine DF; Noseworthy RG, 2016. Distributional status of an introduced land snail Discus rotundatus (rotund disc, Mollusca: Discidae) in Canada. Canadian Field-Naturalist, 130(3):236-247. http://www.canadianfieldnaturalist.ca/index.php/cfn/article/view/1887
Fromming E, 1954. Biology of central European Landgastropoden (Biologie der mitteleuropaischen Landgastropoden). Berlin: Duncker & Humbolt, 404pp.
Frömming E, 1954. Biology of Mid-European Landgastropoden (Biologie der mittel-europaischen Landgastropoden). Berlin, Germany: Dunker and Humblot.
Georgiev D, 2014. First Record of Discus rotundatus (Muller, 1774) (Gastropoda: Discidae) in Bulgaria. Acta Zoologica Bulgarica, 66(4):575-576.
Germain L, 1930. Terrestrial and Fluvial Molluscs (Part One) - Wildlife of France (Mollusques Terrestris et fluviatiles (premiere partie). Faune de France). Paris: Paul Lechevalier, 480pp.
Gireaud, 2007. The Different Species of European Snails (Les Differentes Especes d'Escargots Europeens). http://www.gireaud.net/especes.htm
Giusti F; Manganelli G; Schembri PJ, 1995. The Non-marine Molluscs of the Maltese Islands. Monografie XV. Turin, Italy: Museo Regionale di Scienze Naturali, 585pp.
Grimm FW; Frosyth RG; Scheler FW; Karstad A, 2009. Identifying Land Snails and Slugs in Canada. Introduced Species and Native Genera. Ottawa, Ontario, Canada: Canada Food Inspection Agency, 168pp.
Grimm FW; Schueler FW; Picard I; Forsyth R; Karstad A, 2016. Terrestrial Gastropods of Canada - Discus rotundatus (Muller 1774), Garden Disc Snail. http://www.pinicola.ca/tgspec1.htm
Herbert DG, 2010. The introduced terrestrial Mollusca of South Africa. SANBI Biodiversity Series, No. 15. Pretoria, South Africa: South African National Biodiversity Institute. http://www.sanbi.org/sites/default/files/documents/documents/bioseries15introterrestmollusca.pdf
Hertz CM, 1996. Discus rotundatus (Muller): another land snail sighted in San Diego. The Festivus, 28(8):89-90.
Horsák M; Cejka T; Juricková L; Beran L; Horácková J; Hlavác JC; Dvorák L; Hájek O; Manas M; Ložek V, 2015. Check-list and distribution maps of the molluscs of the Czech and Slovak Republics. http://mollusca.sav.sk/malacology/checklist.htm
Horsák M; Lososová Z; Cejka T; Juricková L; Chytrý M, 2013. Diversity and biotic homogenization of urban land-snail faunas in relation to habitat types and macroclimate in 32 central European cities. PLoS ONE, 8(8):e71783. http://www.sci.muni.cz/botany/chytry/Horsak_etal2013_PLOS-ONE.pdf
Hotopp K; Pearce TA, 2007. Land snails in New York: statewide distribution and talus site faunas. Final Report for contract #NYHER 041129 submitted to New York State Biodiversity Research Institute. Albany, New York, USA: New York State Museum, 91 pp.
Kappes H; Jordaens K; Hendrickx F; Maelfait JP; Lens L; Backeljau T, 2009. Response of snails and slugs to fragmentation of lowland forests in NW Germany. Landscape Ecology, 24(5):685-697. http://springerlink.metapress.com/link.asp?id=103025
Kazubski SL, 1958. Results of investigations carried out on Ciliata and some other parasites of land snails. Wiadomosci Parazytologiczne, 4:666.
Kazubski SL, 1959. Studies on the ciliophoran parasites of the land snails in Poland in the years 1956-1958. Journal of Protozoology (Supplement), 102.
Kazubski SL, 1978. Further investigation on morphological variability in ciliates Myxophyllum steenstrupi (Stein), parasite of land snails. In: 4th International Congress of Parasitology, 19-26 August, 1978, Warsaw. Short communication, Section B. Warsaw, Poland: Organizing Committee, 8.
Kuznik-Kowalska E, 1999. Life cycle and population dynamics of Discus rotundatus (O. Müller, 1774) (Gastropoda: Pulmonata: Endodontidae). Folia Malacologica, 7(1):5-17.
Kuznik-Kowalska E, 2008. Shell variation in the genus Discus Fitzinger, 1833 (Gastropoda: pulmonata: endodontidae). Folia Malacologica, 16(1):1-16.
Liggia B, 2016. WMSDB - Worldwide Mollusc Species Data Base - Gonyodiscus rotundatus (O. Muller, 1774) - ID: 4240000040. http://www.bagniliggia.it/WMSD/HtmSpecies/4240000040.htm
Loreau M, 1983. The diet of Abax ater Vill. (Coleoptera, Carabidae) (Le régime alimentaire de Abax ater Vill. (Coleoptera, Carabidae)). Acta Oecologia/Oecologia Generalis, 4:253-263.
Manganelli G; Bodon M; Favilli L; Giusti F, 1995. Fascicolo 16. Gastropoda Pulmonata. In: Minelli A, Ruffo S, La Posta S, eds. Checklist delle specie della fauna italiana, 1-60.
Morand S; Wilson MJ; Glen DM, 2004. Nematodes (Nematoda) parasitic in terrestrial gastropods. In: Natural enemies of terrestrial molluscs [ed. by Barker GM]. Wallingford, UK: CABI Publishing, 525-557. http://www.cabi.org/CABeBooks/default.aspx?site=107&page=45&LoadModule=PDFHier&BookID=209
Müller OF, 1774. Of worms on earth, and fluviatilium , that is, of the living creatures infusoriorum, helminthicorum, and pots. Volume one. (Vermium terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volumen alterum). Heineck & Faber, Havniæ & Lipsiæ, 214 pp.
National Museums Northern Ireland, 2010. MolluscIreland. Discus (Gonyodiscus) rotundatus (O. F. Müller 1774) Rounded Snail. UK: National Museums Northern Ireland. http://www.habitas.org.uk/molluscireland/species.asp?ID=75.
NatureServe, 2015. NatureServe Explorer: An online encyclopedia of life (Version 7.1). Arlington, Virginia, USA: NatureServe. http://explorer.natureserve.org
Nobre A, 1913. Molluscs of Portugal. I. Terrestrial molluscs, river and brackish water. 2 of issue (Moluscos de Portugal. I. Moluscos terrestres, fluviais e das águas salobras. 2.° fascículo). Memórias Publicadas pela Sociedade Portuguesa de Sciências Naturais, Lisboa, 1:129-343.
Nobre A, 1941. Mollusc fauna of Portugal. II. Land and river molluscs (Fauna malacológica de Portugal. II. Moluscos terrestres e fluviais). Memórias e Estudos do Museu Zoológico da Universidade de Coimbra, 9(124):1-279.
Pilsbry HA, 1948. Land Mollusca of North America (north of Mexico), Vol. 2(2). Academy of Natural Sciences, Philadelphia, Monographs, 3: 521-1113.
Poppe GT; Poppe P, 2016. Shell Encyclopedia. Conchology, Inc. http://www.conchology.be/?t=64
Réal G; Réal-Testud AM, 1988. Malacofauna the land of the island of Corsica historical and updated inventory (La malacofaune terrestre de l'île de Corse: historique et inventaire actualise). Haliotis, 18:43-54.
Reitano A; Liberto F; Giglio S; Grasso; R; Spena MT, 2012. Terrestrial molluscs from the R.N.I. “Grotta Conza” (Palermo, Sicily) (Gastropoda Architaenioglossa Pulmonata). Biodiversity Journal, 3(4):555-570.
Revier H, 1982. Snails killing flies (Diptera Sciorayzidae) in the Netherlands; an initial inventory (Slakken dodende vliegen (Diptera Sciorayzidae) in Nederland; een eerste inventarisatie). Taxonomic Institute of Zoology (Zoological Museum), University of Amsterdam, reports and technical data, 35: 36pp.
Robinson DG, undated. Medical and veterinary aspects - Snails and slugs aren't just agricultural and horticultural pests. Presentation. https://www.wpdn.org/webfm_send/531
Roth B; Sadeghian P, 2006. Checklist of the land snails and slugs of California. Santa Barbara Museum of Natural History Contributions in Science, 3. 1-82.
Salvador RB; Cunha CM; Simone LRL, 2013. The pulmonate snails of Trinidade Island, Brasil. Tentacle, 21:38-39.
Seddon M, 2008. The landsnails of Madeira. An illustrated compendium of the landsnails and slugs of the Madeiran archipelago. Studies in the biodiversity and systematics of terrestrial organisms from the National Museum of Wales. BIOTIR Reports, 2(1-7). 1-204.
Smith KGV, 1989. An introduction to the immature stages of British flies: Diptera larvae, with notes on eggs, puparia and pupae. Handbooks for the Identification of British Insects. London, UK: Royal Entomological Society, 10(14):1-280.
Solymos P, 2008. Quantitative biogeographic characterization of Hungary based on the distribution data of land snails (Mollusca, Gastropoda): A case of nestedness of species ranges with extensive overlap of biotic elements. Acta Zoologica Academiae Scientiarum Hungaricae, 54(3):269-287.
Štamol V, 2010. A list of the land snails (Mollusca: Gastropoda) of Croatia, with recommendations for their Croatian names. Natura Croatica, 19(1):1-76.
Štamol V; Slapnik R; Vukovic M; Kletecki E, 2015. Records of non-marine snails new for Croatia (Mollusca: Gastropoda). Nat. Croat, 24(2):337-344.
Turgeon DD; Quinn JF; Bogan AE; Coan EV; Hochberg FG; Lyons WG; Mikkelsen PM; Neves RJ; Roper CFE; Rosenberg G; Roth B; Scheltema A; Thompson FG; Vecchione M; Williams JD, 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. American Fisheries Society Special Publication 26, second edition. Bethesda, Maryland, USA 526pp.
Turner H; Kuiper JGJ; Thew N; Bernasconi R; Rüetschi J; Wüthrich M; Gosteli M, 1998. Fauna Helvetica 2. Atlas of Switzerland and Liechtenstein of molluscs (Neuchatel Fauna Helvetica 2. Atlas der Mollusken der Schweiz und Liechtensteins). Neuchatel, Switzerland: CSCF, 527pp.
Tyler J, 2016. Glow-worms. http://www.glowworms.org.uk/Tylerbookpt1.html
US Fish and Wildlife Service, 2006. Chittenango ovate amber snail (Novisuccinea chittenangoensis), 5 year review, summary and evaluation. Cortland, New York, USA 12pp. http://ecos.fws.gov/docs/five_year_review/doc1011.pdf
Welter-Schultes F, 2013. Species summary for Discus rotundatus. AnimalBase. http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase/home/species?id=1240
White-McLean J, 2011. Discus rotundatus. http://idtools.org/id/mollusc/factsheet.php?name=Discus%20rotundatus
Winsor L; Johns PJ; Barker GM, 2004. Terrestrial planarians (Platyhelminthes: Tricladida: Terricola) predaceous on terrestrial gastropods. In: Barker GM, ed. Natural enemies of terrestrial molluscs. Wallingford, UK: CAB International, 227-278.
Örstan A, 2003. The first record of Discus rotundatus from Turkey. Triton, 7:27.
Örstan A, 2012. The first record of the European land snail Discus rotundatus (Müller, 1774) from Montreal, Canada (Discidae: Pulmonata). Check List, 8(3):537-539.
ContributorsTop of page
26/02/2016 Original text by:
Norbert Maczey, CABI, UK
Distribution MapsTop of page
Unsupported Web Browser:
One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Please consider upgrading your browser to the latest version or installing a new browser.
More information about modern web browsers can be found at http://browsehappy.com/