There is a very long list of species that are non-native to the UK, many (if not most) are harmful to our native wildlife. I am regularly finding non-native species in my garden as well as further afield, Grey Squirrels are one such example. They were introduced to the UK nearly a century and a half ago from North America and since then they have severely affected our native species, through the severe population decline in Red Squirrels to the predation of young birds and eggs.
You might remember that last year I found several individuals of the slug Ambigolimax nyctelius. It was the first record of this non-native species in Surrey and had most likely come from the nearby garden centre. Well, a few weeks ago I found a small black slimy flatworm under one of the logs in my garden, which upon closer inspection appeared to have two pale lines running down its body. I used this character to identify it, which wasn’t as tricky as I thought it might be. There are 14 species of terrestrial flatworms in the UK, however many are really distinctive, coloured bright yellow or with distinctive head shapes.
Looking through the species in this very helpful PDF, I could see only two species that looked similar to mine: Kontikia ventrolineata and Australopacifica coxii. I originally thought it might be Australopacifica coxii however when I looked closer I could see that on my specimen the two lines were grey and not blue as is more commonly found in that species. So I concluded that my flatworm was most likely to be Kontikia ventrolineata, however as I have never identified any flatworms before I sent a couple of photos to the leading expert on flatworms, Hugh Jones. To my delight he replied and said that there was no doubt that it was indeed Kontikia ventrolineata. He also sent two distribution maps, one before my record had been added and one with my record on the map. I am very pleased to say that this is the first time Kontikia ventrolineata has been recorded in Surrey!
Without my record
With my record added
Ever since I found that first Kontikia ventrolineata I have been seeing more and more under logs and stumps in my garden. This isn’t very good news, as this species is believed to prey on our native small snails and possibly slugs. Therefore the flatworms will be in competition with the thrushes and the hedgehogs, reducing the amount of food for them. They might be insignificant at the moment but if the numbers keep on increasing like they have already, then they will be a major blow for the hedgehog population especially.
Only a week after I found the first Kontikia ventrolineata I found another alien species! This time it was found in our new beetle trap which is baited with bananas. It is tub shaped with a hole in the bottom through which the beetles enter and stay until I check it a few days later. The trap was full of many different types of fruit flies and several wasps but only one beetle, which would have been disappointing if it wasn’t an interesting species.
The beetle was tiny, but identification was aided by the interesting shape and the markings. After a lot of research I was able to narrow it down to a family, Nitidulidae, and from there I eventually reached species level and identified it as Carpophilus hemipterus, also known as the Dried Fruit Beetle. Its favourite food is overripe fruit, which explains its presence in the trap. Although it is native to Asia, it has spread all around the globe on exported fruit and now inhabits all continents apart from Antarctica!
However, looking at the NBN Gateway map for this species (above) it doesn’t appear very common but seems widespread, at least in England. The NBN Gateway doesn’t always show all of the records of a species on the map, so I don’t know if this might be the first record for this species in Surrey outside of London, however it certainly isn’t common!
Carpophilus hemipterus. Not the best photo: the beetle was really tiny!