Fig. 1

Aedes j. japonicus occurrence reported in Europe according to studies published until the end of 2017 plus two online reports from 2018 (coloured symbols; crosses indicate reports of eradication). Dashed outlines and their respective numbers refer to the present populations as mentioned in section “Summary of the European distribution as of 2017”. Aedes j. japonicus findings between 2012 and 2016 from studies by Kampen et al. [6, 42, 44], Walther et al. [43], Werner et al. [33, 45] and Zielke et al. [54] are summarised in Kampen et al. [60]; unpublished data from 2017 are referred to as ‘Walther et al., unpublished’. Hatched areas display Ae. j. japonicus reporting (introduction and establishment) based on NUTS3 level, according to the ECDC Ae. j. japonicus vector map from August 2018 (https://ecdc.europa.eu/en/publications-data/aedes-japonicus-current-known-distribution-august-2018). Hatched areas may be misleading considering the size of the putative distribution areas but are particularly important for following-up affected areas when no recent original data are available, e.g. for Switzerland. The map was created with QGIS, v.2.18.14 (QGIS Development Team, 2018). The base map of Europe and respective administrative areas were downloaded from http://www.naturalearthdata.com