It is hypothesized that cocoons attached to any material were transported by air, eg by NATO aircraft, after which the moths found their favourite hostplant commonly planted.
The finding of an unknown small moth by Dutch amateur moth hunter Hans Huisman in his backyard lead to the discovery that the American Oak skeletonizer (Bucculatrix ainsliella) is invading North West Europe on planted Northern Red oaks (Quercus rubra), a North American tree.
"The finding is unusual", says Erik J van Nieukerken of Naturalis Biodiversity Center (Leiden, Netherlands), "because until recently few insects attacked this North American tree outside its natural habitat." He and co-authors just published a paper on this species in the journal 'Nota Lepidopterologica', a specialist journal for the study of moths and butterflies (Lepidoptera) in Europe.
Northern Red oaks are widely planted in Europe since the introduction in the 17th century, and the tree is important as a timber tree. Only one North American aphid, specializing on this kind of oaks has previously crossed the ocean. "The Red oaks are too different from European oaks to attract many of the specialist insects that feed on those," says Van Nieukerken, "and we usually only see insects that are common on many tree species." The identity was also shown by DNA barcodes showing no difference between European and American populations.
Bucculatrix ainsliella is now common in most of the Netherlands, the northern part of Belgium and adjacent parts of Germany. The researchers expect it to be already more widely spread, and it will possibly invade most of Europe the coming years. Despite its abundant occurrence, it has nowhere lead to any visual damage, although it is known to be a pest occasionally in North America.
After the discovery was announced online and in the Dutch media in 2011, it turned out that many moth photographers and collectors in the
|Contact: Astrid Kromhout|
Naturalis Biodiversity Center