Iceland’s long-held distinction as one of Earth’s two mosquito-free regions has concluded, with scientists confirming the first discovery of the insects in the country following a spring of record-breaking heat.
The confirmation of mosquitoes, specifically the Culiseta annulata species, comes after an insect enthusiast, Björn Hjaltested, found three specimens last week. This finding means only Antarctica now holds the distinction of being truly mosquito-free.
Experts view the discovery as a potential indicator of "significant" shifts in Iceland’s fragile ecosystem, which has historically adapted to cold weather. The Culiseta annulata species is known for its ability to survive colder temperatures.
Hjaltested made the initial discovery in a glacial valley southwest of Reykjavik. He was using a wine-soaked rope as a trap to observe moths when he found two female and one male mosquito.
He immediately recognized them as a novel sight and shared his findings on social media. Hjaltested stated, "I knew immediately that this was something I had never seen before," adding, "The last bastion seems to have fallen."
The specimens were sent to the Icelandic Institute of Natural History. Entomologist Matthías Alfredsson confirmed the identification, noting the species is common in parts of Europe and North Africa.
How the mosquitoes arrived in Iceland remains a mystery. One theory suggests the insects may have traveled via shipping containers or vessels. Hjaltested’s discovery site is approximately 6 kilometers (3.7 miles) from Grundartangi port.
Iceland’s previous mosquito-free status was attributed to its consistently cold climate. The country also lacked sufficient stagnant water, which mosquitoes need for breeding.
However, Iceland recently experienced unprecedented warmth. Temperatures in May typically do not exceed 20 degrees Celsius (68 degrees Fahrenheit) for more than a few days.
This year, temperatures surpassed 20 degrees Celsius for 10 consecutive days in some areas. Egilsstaðir Airport recorded Iceland’s hottest May day, reaching 26.6 degrees Celsius (79.9 degrees Fahrenheit).
Further monitoring in the upcoming spring will be crucial. This will help ascertain if the mosquito species has truly established a permanent presence in Iceland.