The Lime Hawk-moth has spread almost 70 miles northwards
Britain's moth species are spreading north, probably because climate change means they are no longer confined to the south, conservationists say.
At the same time new moths are arriving in Britain from mainland Europe.
Butterfly Conservation has monitored sightings from thousands of volunteers since 2007, in response to research showing moth numbers are in decline.
"Moths have a lot to tell us. Their declines alert us to deterioration in the environment," a spokesman said.
"We're just beginning to analyse what is going to be a vast and internationally important database," Richard Fox, National Moth Recording Scheme manager, added.
"Studying this large group, the moths, will give us a much better indication of what's happening to flies, bees, dragonflies and everything else.
"I suspect where will be a lot of declines. A lot of moths have become considerably rarer over the last 50 years."
The scheme has just notched up its five millionth recorded sighting - a Spectacle moth at Yarner Wood in south Devon.
Using comparisons with historical information it has been possible to get an idea of the rate at which some moths are moving north.
Examples have included the Orange Footman moth, which experts say has spread almost 150 miles northward in three decades from Norfolk and southern England to north Yorkshire.
At the same time the Lime Hawk-moth has spread almost 70 miles northwards, from Humberside to County Durham.
And Butterfly Conservation says that since the turn of the century, about 28 new species have been seen in the UK for the first time, including the beautiful marbled moth, Patton's tiger and the Minsmere crimson underwing.