Iceland Says It Is No Longer Mosquito-Free

Iceland lost the distinction this month of being one of the last places in the world without a confirmed sighting of wild mosquitoes. And their presence was discovered only because of a rope in a garden doused in sugary red wine.

A bug enthusiast named Bjorn Hjaltason has spent years attracting insects to his property using a method known as “wine roping,” in which fabric dipped in sugared wine is used as a lure. Usually, the wine draws moths, according to Matthias S. Alfredsson, an entomologist at the Natural Science Institute of Iceland who occasionally collaborates with Mr. Hjaltason on projects.

But last Thursday, Mr. Hjaltason noticed an unusual bug, said Mr. Alfredsson. Could it be a mosquito? He sent a photo to Mr. Alfredsson, who went to look in person. (Mr. Hjaltason did not respond to requests for comment.)

Soon, Mr. Alfredsson confirmed Mr. Hjaltason’s hunch:

Three mosquitoes — two females and a male — were eventually discovered at the property.

“This is the first time” that mosquitoes have been found in the wild of Iceland, Mr. Alfredsson wrote in an email. The Natural Science Institute announced the discovery in a statement on Tuesday.

The question for Icelandic scientists is whether they will be short-lived tourists or the beginning of a new, native population. But either way, mosquito experts say the discovery is a sign of how rapid climate change and globalization are changing Iceland.

“We should not be surprised that we see mosquitoes popping up in very strange localities,” said Bart Knols, a Dutch mosquito expert and a founder of MalariaWorld, which gathers and shares malaria research.

Iceland has seen a spike in insect life over the past four decades or so, said Gisli Mar Gislason, a professor emeritus at the University of Iceland who studied aquatic insects and is writing a book on Icelandic insect identification with Mr. Alfredsson, Mr. Hjaltason and another entomologist.

Recently, that growth has coincided with the skyrocketing number of international travelers visiting the geographically isolated nation. The torrent of planes, cruise ships and cargo boats gives insects more chances to hitch a ride, Dr. Gislason said.

At the same time, climate change has transformed the country. One Icelandic glacier, Okjokull, has completely melted away while some native plants are at risk of extinction as temperatures rise and invasive species arrive.

“Insect numbers increase with increasing heat,” said Dr. Gislason, who until now had the honor of having caught the only mosquito in Iceland. (In the 1980s, at the main airport, he trapped one flying in a plane that had just arrived from Greenland.)

“With increasing temperatures,” he continued, “There are more opportunities for species from warmer areas to colonize Iceland.”

Enter the mosquitoes. Given that these three were found near Reykjavik, the capital, and an international harbor, they most likely came from abroad, experts said.

“With only three specimens found,” Dr. Gislason said, “I would guess it’s a very recent arrival.”

But with the climate warming, it is plausible they could survive in Iceland, according to Dr. Knols. “We should not be surprised if — maybe just for a short period — that mosquitoes manage to establish themselves and produce the next generation,” he added.

Dr. Gislason, who reviewed photos of the three specimens, said a mosquito population could spread quickly, pointing to no-see-ums (Ceratopogonidae). Those bugs, which also cause itchy bites, appeared only a decade earlier, he said. Now, he added, they are present throughout the country.

“If this population establishes itself, as I presume it will, it may spread as fast as the no-see-ums,” he said.

These specific mosquitoes could also be able to endure the harsh Icelandic climate. Mr. Alfredsson identified them as Culiseta annulata, a variety of mosquito that can survive long periods of freezing temperatures and already lives in the Nordic region, the Natural Science Institute said in a statement.

While it is impossible to know if these are truly Iceland’s first mosquitoes, the country has extensive insect monitoring, meaning a previous population would have most likely been detected, Mr. Alfredsson said. If there were a few mosquitoes in the past, he added, they probably died out without establishing a foothold.

It is not yet clear whether this triad is a fluke or a sign of a new reality; Mr. Alfredsson said more monitoring would be needed to see if they have “truly become established in Iceland.”

For now, the three are sticking around. Currently, Mr. Alfredsson wrote, all three “are stored in my freezer.”