Scientists are appealing to the public to help track down a giant slug which has been invading Britain from Spain.

The Spanish slug is thought to have arrived here on salad leaves but has bred rapidly – laying up to 400 eggs each – threatening British crops.

The invasion has been slowed by frosts in May which killed thousands of them, but scientists are so concerned they have launched and are asking the public to help track them.

The pests eat dead animals, excrement and even their own species. They can grow up to 6in long, lay 400 eggs each, eat crops usually spared by our native slugs and can survive poison pellets.

The SlugWatch website contains information on how to trap the animals and print out kits which help identify them and has been launched to coincide with UK Biology Week.

The biggest fear is that they will breed with native slugs, giving them a greater resistance to cold weather while keeping their keen appetite.

When the species first appeared in Scandinavia a few years ago they bred so quickly that squashed slugs on roads caused serious traffic problems.

The species was first spotted in the UK in 2012 by Dr Ian Bedford, head of entomology at the John Innes Centre.

He counted 350 of them in just one day and when he saw some eating a dead mouse he decided to send samples for identification.

The species turned out to be Arion vulgaris, otherwise known as the Spanish slug. They are thought to have travelled here on imported trees, pot plants or salad leaves.

In an interview with The Observer Dr Bedford said: ‘The Spanish slug is a voracious predator that can survive eating many of the slug pellets that are supposed to kill them.

‘We want photos and sightings from members of the public to help build a picture of how widespread the Spanish slug is.’

Most slugs play an important part in the ecosystem and of the 30 species in the UK only four are classed as pests.

The majority of slugs actually live underground and the ones which can be seen feeding on the surface make up less than 5 per cent of the population.

The gastropods can move up to 16 feet per night and can detect food from 23 inches away.

Spanish slugs vary in colour from bright orange to rusty brown and can be identified by their high numbers and odd diet which also includes excrement.

source: Daily UK