Gardeners have been urged to pick up their torches and hunt in their gardens for slugs as the Royal Horticultural Society issues a plea for data on the disappearing British bug.
There are worries the Yellow Cellar Slug, which is useful for gardens as it feeds on decaying rather than live plant material, is being usurped by the Green Cellar Slug, originally from Ukraine, which arrived in the 1970s.
Since the Green Cellar Slug arrived, numbers of the useful slug are thought to have sharply declined.
While both slugs have large, green-yellow, patterned bodies, the Yellow Cellar Slug has a long yellow stripe running along the centre of its tail.
As slugs are nocturnal, people are being asked to don torches and step out into their gardens after dark in the hope of recording them.
The RHS has asked those with gardens to take photographs showing the top view of each slug, match the slug to the ID guide on the RHS website to see what species it is, keep a note of how long the search took and how many slugs were found, note which plant, if any, the slugs were found on, and to record findings on the RHS’ iRecord page
Imogen Cavadino, Research Assistant at the Royal Horticultural Society, said: “Of the 44 species of slug known to exist in the UK only nine are serious pests.
"Most are important composters and feed on fungi, lichens and algae. Slugs are also a valuable part of the garden ecosystem because they serve as an important food source for birds, hedgehogs and other garden visitors.
"Both cellar slugs feed on detritus, moulds and algae, though they are known to feed on pet food and even old damp wallpaper.
"They are more like the cleaners of the garden and great for the compost heap. There is even a man in Australia who keeps the Yellow Cellar Slugs in his bathroom to feed on/clean the mould from the grout between his bathroom tiles and his shower curtain.
"Yellow Cellar Slugs are found on all continents except Antarctica, though some of these populations may actually be the Green Cellar Slug as the two are so often confused."