THE North-East has witnessed a spate of spectacular dragonfly and butterfly sightings which naturalists believe are the strongest indication yet that global warming is affecting the region's climate.

Traditionally, most butterflies and dragonflies live in the warmer South, but recent years have seen a steady move northward with more species gaining footholds in the region.

The most notable of this year's sightings came on the pond at Rainton Meadows nature reserve, near Houghton-le-Spring on Wearside, the headquarters of Durham Wildlife Trust.

They were spotted by Ian Waller, butterfly recorder for Durham and Northumberland, who found four rare dragonflies, the most spectacular of which was the lesser emperor.

Lesser emperors, dark brown with a bright blue abdomen, are normally found in southern Europe and only in small numbers.

Britain's first record was in June 1996 since when the insect has been seen in southern areas including Cornwall and Cambridgeshire.

This year, however, there have sightings at Rainton Meadows, an unconfirmed one at Boldon, near Sunderland, and one in the Orkneys off the Scottish coast.

On the day he spotted lesser emperor, Ian also saw red-veined darter, a four-spotted chaser and an emperor, all new to Rainton Meadows and rare for the North-East.

Ian said: "The male lesser emperor was the most remarkable of the sightings. I could not believe what I was seeing, it was great. There was a female as well.

"There have been seven or eight sightings nationally of lesser emperor this year and this one rates as one of the top ten ever recorded in this country.

"There has been an influx of migrant dragonflies this year and for the lesser emperor to be recorded in the Orkneys is amazing."

Another indication has been the success of the banded demoiselle damselfly, which has been reported at Billingham Beck Valley country park on the edge of the Teesside town and at Stillington Forest Park north-west of Stockton.

Eighty of the brilliant blue/green creatures, which are common in southern England but rare in the North, have been recorded at a site near Crook in Weardale, and are also found in lower numbers along the River Wear, from Chester-le-Street to Witton-le-Wear.

Butterflies are also supporting the trend, even though it has been a poor year for native species due to the wet and cold spring, which hit breeding and the insects' ability to disperse.

The most spectacular reports have come courtesy of an influx of migrants including painted ladies, red admirals, clouded yellows and an invasion of hummingbird hawkmoths.

One of the most remarkable sightings has been hutchinsoni, the rare cousin of the more prevalent comma butterfly, another species gaining a foothold in the north.

Hutchinsoni are normally associated with warm climates and this year there have been eight reports, including one in the Darlington area.

Another species heading north is the purple hairstreak, with 100 recorded at Eyreholme, near Croft, not far from Darlington, a dozen near Sockburn Hall, also near Croft, and half a dozen from Finchale Abbey.

Gatekeeper butterflies have also been reported in increasing numbers this year.

Ian said: "Several years ago when you looked at the distribution map for purple hairstreak there were only a couple of places where it had been seen singularly, but this year there have been large numbers found.

"So many sightings of butterflies, moths, dragonflies and damselflies normally associated with warmer southern regions suggests that something is definitely happening to the climate.