A SPECTACULAR European butterfly could be attempting to colonise Sussex.

A dozen adult continental swallowtail butterflies have been seen across the county.

Last year’s hot summer led to the largest invasion of continental swallowtails since 1945, with adults laying eggs in a number of gardens in Hastings, Eastbourne and Chichester.

The butterfly – which resembles a species Britons would be more likely to see in a tropical butterfly house, with its striking black and yellow markings and a streamer-shaped tail – finds it difficult to survive winter in the UK’s relatively cold climate.

But the emergence of adults from pupae in recent weeks suggests the mild winter may have helped them survive.

The UK already has a subspecies of swallowtail, the country’s largest species of butterfly but smaller and darker than its continental cousin, which is restricted to the Norfolk Broads.

With a warming climate the continental swallowtail could become a UK resident in the near future, Butterfly Conservation said.

Michael Blencowe, from Butterfly Conservation’s Sussex branch, who has been monitoring the butterflies since they arrived last summer, said: “So far there have been 12 sightings of swallowtails in Sussex this spring.

“Six of these have been seen to emerge from pupae we were monitoring; others have been seen in Peacehaven, Chichester, Chanctonbury Ring and Horsham.

“There are still more to emerge and no doubt many other swallowtails that we don’t know about are roaming the country, so there has never been a more exciting time to head out looking for butterflies.

“This current invasion could be the start of the colonisation of southern England by the swallowtail. In 20 years this butterfly could be a regular visitor to our gardens.”

Meanwhile a rare species of moth has moved into the wildflower meadows at Wickhurst Rise in Portslade.

The Mother Shipton moth has settled among the wild flowers planted by Brighton and Hove City Council.

Council rangers and volunteers collected wildflower seeds from the downs and more than 90,000 were planted around the city during the winter.

Mowing was then reduced to attract wildlife not seen in the area before.