Variabilitat genètica d'Aedes japonicus a Europa i la invasió de l’espècie a Espanya

Abstract

The invasive species Aedes japonicus is native to East Àsia, but it started spreading to New

Zealand in 1990 and since then it has been spreading across Europe and North Àmerica for

the past few decades. In Spain, its introduction was declared in 2018, when it was detected

in Àsturias for the first time. Later, established populations were also found in Cantabria and

the Basque Country. The colonisation of this mosquito is concerning, as it is a biological

vector of several diseases and its dispersion can present a health risk, due to the fact that it

can become a potential epidemiological focus. In order to prevent future health threats, it is

of great interest to determine the dynamics of dispersal and the means by which the species

spreads.

To determine the introduction pathway and dispersal routes of the species in Spain, a

genetic study was carried out using molecular tools, both at the level of genetic diversity and

population structure. The study consisted of 635 samples from different geographical

locations in Europe, the United States and Japan where the species is established. 14

microsatellites were analysed, 7 loci specific to Ae. japonicus and 7 specific to Ae. albopictus,

to increase the resolution of the results.

The analyses carried out have provided conclusive results indicating that the individuals

from Àsturias, Cantabria and the Basque Country show greater similarity with those from

Japan and the United States, but above all with a population from the eastern United States,

indicating that this area could represent the origin of the mosquitoes that colonized Spain.

On the other hand, the mosquitoes from the province of Navarre are very different from

those from the rest of Spain, showing more similarities with mosquitoes from other

localities such as Serbia and especially Germany. This is evidence of an independent

introduction to Navarre compared to the rest of the country.

Based on literature research, it has been observed that the dispersal of the species and its

consequent establishment in new territories is mainly attributed to globalisation and trade,

and the associated international and intercontinental movements. Its spread has also been

facilitated by the species' ability to adapt to new environments and conditions, as well as its

high resistance to cold climates