22 February 2018

First outdoor records of the slug Deroceras invadens from the Slovak Republic

Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011 [previously known as Deroceras panormitanum (Lessona et Pollonera, 1882)] was reliably identified from the Slovak Republic from a greenhouse of the Botanical garden for the first time in May 21, 2003 (Dvořák et al. 2003). The first outdoor records (20 ind.) are known from the garden centre in the City of Bratislava (August 1, 2017), recent record (15 ind.) came from Stupava town, SW Slovakia (February 18, 2018).

Its origin is not fully clear but it may come from Italy (details in Reise et al. 2011).
D. invadens is a small slug (length up to 40 mm) of much variable coloration – from creamy-brown or brown to black, often with darker spots. The species cannot be mistaken for any other Deroceras species because of the distinct appearance of its penis: horseshoe-shaped penis has a tuft of long processes of the penial gland.
D. invadens inhabits open cultural landscape (fields, fallows, gardens and parks), ruderal environments and is often found in greenhouses (e.g. Wiktor 2001).

The unique, horseshoe-shaped penis of the slug Deroceras
invadens (photo J.M.C. Hutchinson).

The worldwide occurrence of the slug Deroceras invadens (© J.M.C. Hutchinson, 2017)

Distribution map of  Deroceras invadens in Slovakia (last updated 11 Sept 2020).


Dvořák L., Čejka T. & Horsák M. 2003. First record of Deroceras panormitanum (Gastropoda, Agriolimacidae) from Slovakia. Biologia, 58(5): 917–918.
[2] Reise H., Hutchinson J., 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).
[3] Wiktor A. 2001. Deroceras (Deroceras) panormitanum (Lessona et Pollonera, 1882) – a new introduced slug species in Poland (Gastropoda: Pulmonata: Agriolimacidae). Folia Malacologica, 9(3).

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