A further northward expansion of the invasive land snails Monacha cartusiana and M. Fruticola (Stylommatophora: Hygromiidae) in Eastern Europe

Land snails of the genus Monacha are shown to have expanded widely northward in Eastern Europe during the last decade. Previously their ranges there were limited to Southern Ukraine, Caucasus and several isolated colonies in Western Ukraine. Our new reports cover all parts of Ukraine, as well as some regions of southern Belarus and western Russia. We have sampled 5 large colonies of M. cartusiana in Kyiv region (Central Ukraine) and one in Kharkiv city (northeastern Ukraine), as well as two colonies of M. fruticola in Kyiv city. We also report 72 new records of the subgenus Monacha (M. cf. cartusiana) in Eastern Europe, based mostly on the photographs from citizen science databases (iNaturalist, UkrBIN). The distribution of M. cartusiana around Kyiv city has shown an especially rapid and wide expansion; we report on 36 colonies, some of which are very abundant and cover several tens of hectares each, while the oldest known record of Monacha in this region is only from 2017. Origin, expansion and perspectives of the Monacha species in Eastern Europe are discussed.

Expansion of the invasive Balkan slug Tandonia kusceri (Stylommatophora: Milacidae): A new frontier in northern Ukraine and other new records

The distribution of the invasive slug Tandonia kusceri is reviewed and mapped with our new findings and previously unpublished recent reports based on photographs from citizen science databases (iNaturalist, UkrBIN). Two new colonies of T. kusceri were found and monitored in Kyiv city (Northern Ukraine) during the 2021–2022. These colonies are about 350 km north from the nearest previously published records of this species, as well as any other species of Milacidae in Eastern Europe. The slugs inhabit the urban open and semi-open landscapes of Kyiv city together with several other invasive molluscs, in one locality notably together with Oxychilus translucidus, Harmozica ravergiensis and Xerolenta obvia. One specimen of T. kusceri was found in a basement of a private estate in Radyvyliv town (Rivne region, Northern Ukraine) in 2020, but it is unknown whether it represents an established colony. Previously unpublished reports of T. kusceri on iNaturalist include two reliable findings from the Caucasian region, in Georgia and Russia, both in 2021. These are the first reports of any Tandonia in Caucasus, as well as in the mentioned countries, with one in Georgia being the eastmost frontier for this genus. In addition to a previously published 2013 report of T. kusceri near Chicago, USA, there are multiple iNaturalist reports of this slug in southern Ontario, Canada (600 km east of Chicago), starting from 2017. Moreover, there are several new reports of T. kusceri in Ukraine, including Kherson, Dnipro, Kryvyi Rig, Marhanets and Kamianets-Podilskyi cities. Considering that most of our new T. kusceri records are from the 2020s, it is most likely that slug has invaded these regions very recently and is still continuing to expand northward and eastward in Europe. This species is expected to further extend its range both in Europe and North America.

New Serbian records of the slug Tandonia kusceri (H. Wagner, 1931) (Gastropoda: Eupulmonata: Milacidae) suggest its continuous dispersal to the north

Tandonia kusceri (H. Wagner) is a terrestrial slug native to the Balkan Peninsula (S. Serbia, N. Macedonia, Bulgaria and Dobrudja region of Romania) and the European part of Turkey. In Serbia, it was known mostly from the southern regions. The northernmost locality (Palić settlement, near Subotica) reported here suggests that the slug’s distribution is nearly continuous from its native range until Slovakia. The new record was first recognised from the pictures posted on a Facebook group for insect identification in 2021. The identification was subsequently confirmed by anatomical examination. This further emphasises the importance of social media in monitoring the spread of invasive invertebrates.

Two new alien slugs, Krynickillus melanocephalus Kaleniczenko, 1851 and Tandonia kusceri (H. Wagner, 1931), are already widespread in Hungary

Two slug species (Krynickillus melanocephalus Kaleniczenko, 1851 and Tandonia kusceri (H. Wagner, 1931)) are reported from Hungary for the first time. Identification was supported by anatomical examination in both, and molecular data in the latter species. A citizen science survey applying a Realtime Social Networking Service (RSNS) method using Facebook posts revealed that both species are already widespread in Hungary, i.e. Krynickillus melanocephalus is reported from 14 and Tandonia kusceri from 25 sites. So far, we received no reports on any damage caused by these two slug species. Nevertheless, we treat them as potential horticultural pests requiring further attention.