Sep 11, 2021
Saw this funky slug on my morning walk yesterday so I decided to do some research. Turns out it’s possibly a Spanish slug (Arion vulgaris), which is a highly invasive species and is destroying a lot of UK gardens (it’s also known as the killer slug). Interestingly enough, Spanish slugs didn’t originate in Spain. Their place of origin isn’t really known for certain but they were first recorded in Britain in 1954.
Alternatively it could also be a common red slug (Arion rufus) or a black slug (A. ater), which are all closely related species. Unfortunately you can only differentiate them through dissection since each species is distinguished through the differences in their genitalia, so we’ll never know.
Fascinating stuff!