Researchers of the HUN-REN Centre for Agricultural Research Plant Protection Institute (HUN-REN CAR PPI) have reported five terrestrial slug species from Hungary, either for the first time or confirming earlier unreliable records. A paper in which researchers reported detailed information about the identification methods, external morphology, anatomy and Hungarian records of these species was published in BioInvasions Records.
The research focusing on identification problems of Hungarian slug species has been going on for five years in the HUN-REN CAR PPI involving Ágnes Turóci and Dr. Barna Páll-Gergely. They have already detected hitherto unknown slug species in the Hungarian fauna in 2020, the black-headed slug (Krynickillus melanocephalus Kaleniczenko, 1851) and the keeled slug (Tandonia kusceri (Wagner, 1931)), which are widely distributed in the country.
The introduced species from the top: the green cellar slug, the rough jet slug, the Iberian threeband slug, the Balkan threeband slug and the tramp slug. The figures are proportional, scale: 10 mm. (Photos: Ágnes Turóci)
The researchers presented the following species in their paper: the green cellar slug (Limacus maculatus (Kaleniczenko, 1851)), the tramp slug (Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011), the Iberian threeband slug (Ambigolimax valentianus (A. Férussac, 1821)), the Balkan threeband slug (Ambigolimax parvipenis Hutchinson, Reise & Schlitt, 2022), and the rough jet slug (Milax nigricans (Philippi, 1836)). Beyond the external morphological characters and the detailed anatomical study, the researchers provided DNA sequences underpinning the species-level identity of the slugs.
The introduced slug species mostly came from the Mediterranean Region, certain regions of the Balkan, the Caucasus and the coastal region of the Black Sea.
The green cellar slug was only found in two districts of Budapest, from the Herman Ottó street (II. distr.) and the Böszörményi street (XII. distr.). The tramp slug was detected in the Füvészkert (the Botanical Garden of the ELTE Eötvös Loránd University) and 14 garden centres of Budapest. The Iberian threeband slug was found in the Füvészkert and 10 garden centres of Budapest. The Balkan threeband slug was found in five, and the rough jet slug was collected in two garden centres of Budapest.
Beyond the discovery of the Hungarian fauna, this result is also significant from the perspective of agriculture and horticulture. Amongst the 30 slug species in Hungary, there are approximately 5–10 actual or potential pest species. We have limited knowledge of the damage caused by the currently discovered species, but some of them are known as occasional invasive species and serious pests in other countries, such as the Iberian threeband slug or the tramp slug.
Because most records came from garden centres, these habitats may play a crucial role in the spreading of non-indigenous species. They can serve as potential introduction routes through international trade and we assume that these species have already spread countrywide by means of horticultural products.
This demonstrates the importance of continuing to check for additional introduced species.