Stigmella aceris (Lepidoptera: Nepticulidae), a new leafminer of maples in The Netherlands and Belgium

Leafmines of Stigmella aceris have been found since 2004 in Posterholt, Limburg, on Field Maple (Acer campestre) and Norway Maple (A. platanoides). In 2006, after focused searching, the species was discovered as being common in the province of Limburg and neighbouring Germany (Nordrhein-Westfalen), while the species had never been recorded there before. Mines were also found for the first time in the Eifel mountains, Germany, and in Belgium in four localities in the south. The sudden appearance is paralleled by an expansion in England. Possible explanations for this expansion are the increased planting of the host trees almost everywhere, and the mild winters. These favour the hibernating adults: there are strong indications that S. aceris is the only nepticulid species in Central and West-Europe that hibernates as adult. The European distribution shown is based on a large sample of available literature, collection data and data received from colleagues. Details can be obtained from the senior author.