Eight new slugs found in Britain by Cardiff researchers
Eight extra species of slugs have been identified in a study by Cardiff researchers who say they may pose new threats to gardeners and agriculture.
The incomers have probably come from continental Europe - Spain, France, Italy, Bulgaria or Ukraine.
They have been included in a new guidebook with the 36-previously known slug species.
National Museum Wales scientists worked with experts from Cardiff University and the Conchological Society.
In their two-year study they used DNA, anatomical techniques and digital photography to check each slug's identity and ensure the guidebook was published after collecting slugs from across Britain and Ireland.
Museum zoologist Dr Ben Rowson said he and colleagues, Bill Symondson from Cardiff University and Roy Anderson from the Conchological Society, were amazed to find so many species they did not recognise.
Some were obvious at first glance, but others were more subtle and needed more analysis to confirm they were different.
The researchers believe each of the new species is either recently introduced or has simply been overlooked.
Among their discoveries were two species of short-keeled slugs thought to be recent imports from Italy. One, found in Yorkshire, is enormous at up to 15cm long but seems to be found only at one site.
Dr Rowson said: "We found one small potato-eating species (Tandonia cf.cristata) in allotments in Wales, a churchyard in western Ireland, and waste ground on the Isle of Wight.
"It seems to have been introduced from Bulgaria or Ukraine, and has already bred and been spread around unnoticed.
"Worries about slugs rise and fall with the seasons or weather, but to find all these extra species lurking there is a real concern."
The scientists' guidebook, published this month by the Field Studies Council, includes photos of all British and Irish slugs, some of which they say are surprisingly attractive and not all of which are pests.
But the team are still uncertain about the identity and origins of some of the extra species and say some may even be new to science as there are several parts of Europe where undescribed slug species are thought to occur.