The Asian tiger mosquito Aedes albopictus (Diptera: Culicidae) in Central Germany: Surveillance in its northernmost distribution area

The invasive Asian tiger mosquito Aedes albopictus has recently been observed in southern Germany for the first time to reproduce and even overwinter north of the Alps. After the accidental capture of adult specimens in Jena, German federal state of Thuringia, in mid-2015, regular inspections brought forth developmental stages until autumn 2015, indicating local reproduction. Surveillance activities implemented in 2016 showed larvae already in early May, suggesting overwintering, and throughout the season until late October, although population densities remained low. Further sporadic specimens found in 2017 argue for establishment. Jena is located in Central Germany, north of all known distribution areas of Ae. albopictus, with the area of the municipality affected by the tiger mosquito characterised by a relatively mild climate. To check the suitability of the local climate for Ae. albopictus, winter temperatures, measured in a cemetery of Jena where larvae had regularly been found in 2015 and 2016, were analysed and compared with two sites of establishment in southern Germany. The conditions were similar at all three locations, suggesting that the Jena population might also be able to survive in the long term. While the municipality authorities have been informed and education of the Jena citizens to avoid producing potential breeding places has started, insecticidal control has not yet been implemented.