One evening in early October, a rather splendid looking moth was found sitting on the doorstep of a Wimbledon house.

Of medium size, wings were coloured a very pale whitish-blue with brownish-black margins.

I identified the specimen as a female boxworm moth (pictured), a rather ugly name for such a beauty.

Non-British, it is a native of East Asia where it is considered something of a pest as the larvae feed on and can completely defoliate their foodplant box (buxus).

Only very recently added to the extensive British moth list, it is thought that the species arrives here either as an egg or larva on imported evergreen box plants.

As yet it is very rare but with time could possibly become established.

Accidental introductions of alien insects are not uncommon, many being imported on plants or timber products. Some gall wasps which cause abnormal growth on a variety of trees were introduced on imported timber many years ago.

For example, the familiar marble gall occurring widely on oaks contains high levels of tannic acid and in the nineteenth century the galls were purchased from the middle east for the manufacture of dyes and inks so the tiny greenfly-sized wasps escaped and spread nationwide.

Another gall, the unsightly deforming knopper, arrived from the Continent about forty years ago and initially, scientists worried about its effects on the acorn crop.

However, oaks have so far withstood the onslaught and enough acorns survive each autumn to perpetuate he iconic oak.