There are only two!
In the summer, I photographed an unidentified slug and posted it on iSpot to see if anyone knew what it might be. Recently someone tentatively commented on the observation and said that it might be Ambigolimax nyctelius, the Balkan Threeband Slug. If you have a look at the National Biodiversity Network map for this species, you will see that there are few records for this species (only five!) so I was quite excited!
I emailed Martin Willing, the mollusc recorder for Sussex, and he replied saying that it is likely that the slug is Ambigolimax nyctelius! He couldn’t be certain though, as it needs dissection to reliably identify it. Therefore he forwarded my email to Dr Ben Rowson, the curator for Mollusca at the National Museum Wales. Dr Rowson replied asking if I could confirm if I still had the specimens, which I didn’t, and if I could send some specimens to him for dissection. I sent two new ones along with one of the original three in a pot to the museum, a concept my mum found quite comical. It was probably the idea of three slugs going on holiday to Wales!
He received the slugs surprisingly quickly and he was also kindly quick to identify them. He replied with the scenario I was hoping for: the specimens were of two different Ambigolimax species: Ambigolimax valentianus (the Greenhouse Slug) and Ambigolimax nyctelius (the Balkan Threeband Slug).
What concerned me is that he only received two specimens. The image that immediately sprang to mind was one of a slug crawling around a Welsh post office or somewhere in a postman’s bag in Cardiff. However when I asked about the third slug, he replied saying that the other two slugs were in fact cannibal slugs! I wasn’t expecting that!
Both of these species are special as they aren’t native to this country, the Greenhouse Slug is an alien from Spain; and I’m assuming the Balkan Threeband Slug comes from the Balkans, but there is little information on this little-known species. They are usually imported here by accident in pot plants and survive and breed well in greenhouses (hence the common name of Ambigolimax valentianus). The most obvious place these slugs could have come from is our local garden centre, Haskins. It’s still about a mile away (as the slug crawls)! Most of their route, if they do come from there, is through suitable woodland. Therefore I’m surprised that they’ve come so far. I’m hoping this is because my efforts at creating a wildlife garden are paying off!