First record and establishment of the mosquito Aedes albopictus in Spain.

The invasive mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) was detected for the first time in Spain, in Sant Cugat del Vallès, a city in the north-east of the country (41 degrees 28' N, 2 degrees 4' E, altitude 120 m), during August 2004. A male and one larva were collected in the backyard of a house and in a tree hole, respectively. Dense populations of adults and larvae were found in subsequent surveys, confirming the establishment of the species in the area. This is the first report of the establishment of this species in the Iberian Peninsula.