The mosquitoes they also arrived in Iceland, one of the two countries in the world, together with Antarctica, which did not have them. Björn Hjaltason – a local entomology and ornithology enthusiast – captured 3 specimens of the species Culiseta annulata in Kiðafell, in the western part of the island, about 32 kilometers north of the capital Reykjavik. The cold island in the Atlantic Ocean was considered inhospitable for these insects until a few days ago. The cold temperatures and the volcanic composition of Iceland had “saved” the inhabitants from the annoying buzzes and stings. The discovery of two females and a male, who may have arrived on the island via ships or containers, for researchers it is not so surprising, for some time a possible arrival of dipterans in this land has been hypothesized, favored by climate changes and the increase in temperatures which leads to the melting of glaciers. Iceland experienced record temperatures in 2025 as described by the Icelandic Met Office and World Weather Attribution reports. It is still early to say that the certain cause is temperature variations, studies and monitoring will be needed to see if these specimens will resist the winter and settle on the island permanently, leaving Antarctica as the last land free of mosquitoes.
On October 16, Björn Hjaltason claimed to have seen what he described as “a strange fly” and caught it. With the collaboration of Matthías Alfreðssonan entomologist from the Institute of Natural Sciences of Iceland, the three specimens in total – two females and one male – have been identified as belonging to the species Culiseta annulata.
It is a large mosquito (6-7 mm), dark brown in color and recognizable by the whitish spots on the abdomen and the white bands on the legs. It is widespread in Europe (more common in the north), North Africa, Asia Minor and south-western Asia and is a potential vector for virus And pathogensincluding Tahyna virus, avian plasmodia, equine arboviruses, myxomatosis virus, and West Nile virus. Culiseta annulata is known to be a species adapted to the coldcapable of overwintering without going into diapause – a period of quiescence during which the organism does not feed, does not move and stops its development.
The absence of mosquitoes in Iceland so far was not only due togeographic isolation (900 km from the nearest mainland), which makes their arrival difficult. The main reason lay in the unique climatic and environmental conditions of the island. Unlike other cold countries where mosquitoes survive by hibernating pupae Under the ice, Icelandic winters are too unstable. THE frequent and rapid freeze-thaw cycles they interrupt the hibernation of the pupae, preventing them from completing the life cycle. Furthermore, the chemical composition of stagnant watersinfluenced by the volcanic soil, is inhospitable for the deposition of eggs and the survival of the larvae.
2025 was a year of record temperatures for Iceland characterized by an intense heat wave in the spring months. In May, as reported byIcelandic Met Officetemperatures reached or exceeded 20 °C for 10 consecutive days (in recent years this happened for a maximum of 2-3 days), the highest temperature ever for the month in question was recorded at Egilsstaðir airport, 26.4°C and other areas of the country exceeded seasonal averages by more than 10°C. A study by World Weather Attribution claims that these heat waves are and will be increasingly frequent and likely due to climate change, altering ecosystems and favoring the settlement of “alien” species in these habitats.
Further monitoring will be necessary in the spring to see if this is a temporary appearance or if mosquitoes in Iceland will be able to survive the winter and settle permanently on the island.
