Genomic and functional study on the Tiger Mosquito, Aedes albopictus, in Italy

In few decades Aedes albopictus has spread from its' native range in south-east-Asia all over the world. In Europe this mosquito species has been described in Albania and Italy first and has nowadays expanded to all Mediterranean and east-European countries. Aedes albopictus is also a known vector of Dengue (DENV) and Chikungunya (CHKV) and has been responsible for two CHKV epidemics in Italy, becoming thus an increasing public health concern. Despite this, little knowledge is available on the effectiveness of insecticides commonly used to control adult populations of this species as well as on invasion history of European populations. We here present first evidence of resistance to pyrethroids in Aedes albopictus populations from Italy, which raises alarm on the effectiveness of these control measures in the future. Moreover, we complement this evidence with genomic analysis of 9 Ae. albopictus populations collected across Italy, as well as 1 population from Greece and 1 from Albania, showing occurrence of multiple invasions initiated from large propagules and followed by genetic drift and admixture among different source populations, which created a complex genomic pattern with generally low levels of differentiation and weak signatures of isolation by distance among populations.