Finnish mosquito distributions mapped for first time since 1970s

Many people unwillingly experience the multitude of mosquitoes in Finland - but which species are they? Mosquito distributions have not been systematically studied for decades, however, a new study on mosquitoes collected between 2012 and 2018 reveal larger distributions for many species previously known to occur in Finland. Four species that were previously only reported from Åland are also confirmed on the Finnish mainland for the first time.

Over 52,000 adult and immature mosquitoes were collected from around the country, from all 19 regions, as part of doctoral student Lorna Culverwell’s ongoing research on the mosquitoes of Finland. From these collections it was possible to map the current distributions of 40 of the 43 native mosquito species.

Results confirm the presence of an additional four species, Anopheles maculipennis s.s., Anopheles claviger, Aedes geminus and Ochlerotatus sticticus on mainland Finland when compared to historical records. At least nine species have much larger distributions than have been previously reported.

One factor that may play a part in the changes is a warming climate, since many differences in distributions included species being collected further north than in previous studies.

Updating the species distribution records is important, as understanding which mosquito species are present in an area gives, in turn, a degree of understanding about which pathogens are potentially able to be spread by the mosquitoes in Finland.

“At least 21 of the 43 mosquito species recorded in Finland are either potentially or demonstrably vectors of one or more mosquito-borne pathogens already established in Finland or circulating elsewhere in Europe” says Culverwell.

In addition to the endemic mosquito-borne pathogens, as the climate warms the potential for other pathogens from more southern locations, as well as invasive mosquito species, to become established in Finland and survive the winter is increasing.

“The distribution data presented herein are therefore a fundamental backbone upon which future studies or pathogen transmission models can build to predict and prevent the spread of mosquito-borne agents of disease” Culverwell points out.

Further information:
Lorna Culverwell, doctoral student, University of Helsinki
E-mail: lorna.culverwell@helsinki.fi

Reference: Culverwell, C.L., Uusitalo, R.J., Korhonen, E.M., Vapalahti, O.P., Huhtamo, E. & Harbach, R.E. (2020) The mosquitoes of Finland: Updated distributions and bionomics. Medical and Veterinary Entomology. DOI: doi.org/10.1111/mve.12475