Recently discovered Aedes japonicus japonicus (Diptera: Culicidae) populations in The Netherlands and northern Germany resulted from a new introduction event and from a split from an existing population

Abstract

BackgroundOriginally native to East Asia, Aedes japonicus japonicus, a potential vector of several arboviruses, has become one of the most invasive mosquito species in the world. After having established in the USA, it is now spreading in Europe, with new populations emerging. In contrast to the USA, the introduction pathways and modes of dispersal in Europe are largely obscure.MethodsTo find out if two recently detected populations of Ae. j. japonicus in The Netherlands and northern Germany go back to new importations or to movements within Europe, the genetic makeup of mosquito specimens from all known European populations was compared. For this purpose, seven microsatellite loci from a representative number of mosquito specimens were genotyped and part of their mitochondrial nad4 gene sequenced.ResultsA novel nad4 haplotype found in the newly discovered Dutch population of Ae. j. japonicus suggests that this population is not closely related to the other European populations but has emanated from a further introduction event. With five nad4 haplotypes, the Dutch population also shows a very high genetic diversity indicating that either the founder population was very large or multiple introductions took place. By contrast, the recently detected North German population could be clearly assigned to one of the two previously determined European Ae. j. japonicus microsatellite genotypes and shows nad4 haplotypes that are known from West Germany.ConclusionAs the European populations of Ae. j. japonicus are geographically separated but genetically mixed, their establishment must be attributed to passive transportation. In addition to intercontinental shipment, it can be assumed that human activities are also responsible for medium- and short-distance overland spread. A better understanding of the processes underlying the introduction and spread of this invasive species will help to increase public awareness of the human-mediated displacement of mosquitoes and to find strategies to avoid it.

Aedes albopictus and Aedes japonicus - two invasive mosquito species with different temperature niches in Europe

“…Currently , Ae. japonicus is known from six European countries [30], including Belgium [26], The Netherlands [30], and is regarded as established in Switzerland [26], Austria and Slovenia [29]. Since 2008, Ae.…”

“…albopictus and from Schaffner et al [26]; Huber et al [27]; Huber et al [19]; Krebs et al [28]; Zielke et al [29]; Melaun et al [18] and Zielke et al [30] for Ae. japonicus .…”

Occurrence and Spread of the Invasive Asian Bush Mosquito Aedes japonicus japonicus (Diptera: Culicidae) in West and North Germany since Detection in 2012 and 2013, Respectively

“…By contrast, little information exists on where the other European populations came from, how and where they entered Europe and how they dispersed within Europe. Molecular population analyses showed two microsatellite genetic signatures in Europe suggesting that at least two independent introduction events took place [10, 11]. …”

Hamburger Klimabericht – Wissen über Klima, Klimawandel und Auswirkungen in Hamburg und Norddeutschland

“…sind, wie im Fall der asiatischen Buschmücke (Ochlerotatus [Oc.] japonicus), in einigen Bundesländern bereits heimisch geworden Huber et al 2014;Zielke et al 2015). Andererseits traten in Südeuropa die ersten autochthonen exotischen Infektionen wie das Chikungunya-und das Dengue-Fieber auf, die von Mücken übertragen werden (Rezza et al 2007;Gould et al 2010).…”