The invasive Asian tiger mosquito Aedes albopictus (Diptera: Culicidae) in Germany: Local reproduction and overwintering

Within the framework of a German mosquito monitoring programme, the ‘Mueckenatlas’ (mosquito atlas) has been established as an instrument of citizen participation in mosquito mapping. In 2015, a strikingly large number of Aedes albopictus, which had not been considered established in Germany, was submitted. Three of six collection sites showed local reproduction, with demonstration of developmental stages over three months at two sites. The third populated site was checked only once in October. Developmental stages of Ae. albopictus were found again at these three sites in spring 2016, including one site in southeastern Germany where reproduction had already been documented in 2014. Although population genetic analyses performed on specimens collected at the latter locality in 2014 and 2015 did not provide proof for hibernation, the finding of developmental stages at this and two other very same sites as in the year before and at very early times in the season strongly suggest accomplished overwintering of Ae. albopictus in Germany. Obviously, the second extremely mild winter in Germany in a row and ongoing adaptation of Ae. albopictus to the temperate European climate allow the species to push northwards from endemic regions in the south. Due to the vector competence of Ae. albopictus for numerous pathogens, including dengue, chikungunya and Zika viruses, action should be taken immediately after the detection of local reproduction to eliminate the populations.