Meet the new bugs

It all started with Pholcus, the Daddy-long-legs Spider. This is the long-legged beast with a body like a rice crispy living in the corner of the room on a scaffolding of fine, white threads. Slim, quiet, usually motionless, Pholcus is the new house spider, the champion bug of the all-centrally-heated, super-clean environment. It is pretty clean itself. One barely notices its subtle webs and it never bounds across the carpet in that un-nerving way just as Coronation Street comes on.

In fact, when Pholcus is around you probably won't have much trouble with the bounding sort of spider. It will have eaten them all, along with most of the gnats, mosquitoes and clothes moths that have had the temerity to enter without knocking. Bear that in mind when you reach for the feather duster. A thriving clan of Pholcuses should, in justice, add a couple of thousand to the house value.

The point about Pholcus is that no one except a spider expert had ever set eyes on it until the late Eighties. It is one of a swarm of creepy-crawlies that are quietly, and in most cases benignly, moving into gardens, urban spaces and even houses. Some, like Pholcus, are hitherto rare or retiring beasts that have, for some inexplicable reason, exploded all over the landscape, like speed bumps or wheelie bins. Others are immigrants, asylum seekers from distant lands that have arrived, liked the look of the place and settled.

Take the moth they are all talking about, the Tree-lichen Beauty. This dusky little moth with attractively green-washed wings was barely known in Britain until this year. Then, last June, a brightly-lit moth trap was run on the roof of the Houses of Parliament. Next day, as MPs gathered round, there sitting quietly on an egg box was the fabled rarity. It might have looked like a stunt except that another moth trapper attracted more than 70 of them to his London garden. With astonishing speed, the Tree-lichen Beauty has become one of the commonest moths in London.

It has, says Mark Parsons, head of moth conservation at the charity Butterfly Conservation, been a "phenomenal year for moths". We are getting humid nights at the time when migrant moths are crossing the Channel, propelled northwards by population explosions in their native countries. September is the month for migrant moths. On these balmy nights the south coast glitters with the lights of powerful mercury-vapour moth-traps.

Parsons talks of the moths that are arriving from perhaps as far as Eastern Europe. There has been a glut of Eastern Bordered Straws and a burst of records of the Many-lined, a moth that had been considered extinct in Britain. One lamper found himself in the midst of upwards of 40 dive-bombing Convolvulus Hawkmoths, a great grey moth built for speed despite having a body the size of a shrew's. This moth is one of the "target species" for National Moth Night on 23 September, organised by Butterfly Conservation and the magazine Atropos, when people are urged to take part in a stocktaking of the moths that are about at that time.

New arrivals proliferate in other groups too. We have a new bumblebee, Bombus hypnorum, too new to have yet acquired an English name. First spotted in the New Forest in 2001, this chunky bee with a pretty ginger back and white tail has since been spotted all along the south coast and the Thames estuary. In Europe it is a bee of urban parks and gardens. But future bees will have to contend with another newcomer, the Bee-wolf. This charismatic killer looks like a wasp. But instead of jam and fallen fruit it eats honey bees. In almost any gravel pit south of the Humber Bee-wolves are carrying honey bees back to their nest slung beneath them like a load-carrying helicopter. They are decimating hives up and down the country.

Meanwhile, they are rewriting the field guides on the watery world of dragonflies. Dragonflies are powerful fliers and some have no trouble crossing the Channel or even the North Sea. And they are mating and egg-laying in shallow, summer-warmed pools near the coast. One of them is the Lesser Emperor dragonfly, a native of the Mediterranean, easily spotted by the blue patch where the wings come together. First recorded in 1996, it now forays over large ponds and lakes from Cornwall to Suffolk. From its point of view southern England may be the new Madeira.

But, says Stuart Hynes, an entomologist at the Natural History Museum, the beast that has generated the most letters this year is the Wasp Spider. More than any other new bug this one brings in a distinct whiff of the tropics. Its un-English livery of yellow, black and white stripes is unmistakable. But until this year the Wasp Spider was a reclusive beast lurking in the wilder bits of the south coast. Not any more. "There has been a 200 per cent increase in reports from gardens", says Hynes, "especially from suburban gardens in London and the Thames estuary". Look for them in long grass or low shrubberies when the female sits in the middle of an orb web. Its presence is "almost certainly benign", says Hynes. Only don't pick it up. Although they don't sting, it is one of 12 or so British spiders that can bite.

These are exciting times for new bugs. There is a dynamic in the normally fairly stately invertebrate world that is unprecedented. More species than ever before are becoming naturalised in Britain and increasing at mind-boggling speed. In an echo of the political world it is as if Britain's insects and spiders are being "Europeanised" before our eyes. This year we have seen butterflies from Poland, beetles from Hungary, dragonflies from Spain and moths from France and Holland. It is, you might say, the year of the Euro-bug.

It is easy to put it all down to climate change. The warming weather must play an important part but the Euro-bugs will also be responding to more benign changes in our shared environment. Euro-bugs like gardens and parks. They are responding to cleaner air in cities and finding opportunities in gravel pits and green roofs. Global change theories overlook the enterprising skills of insect kind. Maybe one day some Alan Sugar of a bug will discover possibilities in speed bumps and wheelie bins.

National Moth Night (www.nationalmothnight.info)

Coming soon?

Broad scarlet
This tomato-red dragonfly from Africa has reached the Channel coast. The open sea won't stop it for long. Look out for it in warm shallow pools with dense vegetation near the south coast.

Jersey tiger moth
All right, this brilliantly coloured moth is here already around Torquay. But a spate of new records suggests it is about to become familiar to Londoners. They like gardens and in hot weather tend to congregate in shady, sheltered places. A garden shed, for instance. Or a garage.

Violet carpenter bee
Those big black bees you see buzzing around the Mediterranean are moving north. One was seen in Worthing, Sussex, a few years ago gnawing into a garden bird table. Sightings are getting more frequent, especially on garden globe thistles. Fortunately they are not as aggressive as they look.

Camberwell beauty
Will it ever return to Camberwell? More than 100 of these lovely butterflies, whose dusky velvet wings give it the alternative name of "mourning cloak", visited East Anglia this year. Our winters are thought to be too damp for it to hibernate successfully, but that may soon change.

Capricorn beetle
A long shot, admittedly, but one of these bolshiest of beetles turned up in Warwickshire in 2005 and another in Llanelli last June. Both were probably brought into the country in imported oak timber. It only needs two amorous beetles, a handy oak stump and we're off.