Iceland, once among the last mosquito-free places on Earth, has confirmed the arrival of at least a few Culiseta annulata mosquitoes this year. The discovery, announced by the Natural Science Institute of Iceland (NSII), raises questions about whether these insects will be able to establish a permanent population and what impact this could have on the island’s ecosystem.
A New Resident in a Unique Environment
The initial discovery occurred in mid-October when local resident Björn Hjaltason captured two female and one male mosquito using a ribbon soaked in red wine on a farm near Reykjavík. This represents the first confirmed presence of these insects in Iceland, leaving Antarctica as the only mosquito-free continent. The arrival is significant because C. annulata is more of a nuisance than a danger; they do not transmit human diseases.
How Did They Get There, and Will They Stay?
While the exact means of transportation remain unclear, scientists believe human activity is the most likely explanation. Airplanes have previously carried mosquitoes to Iceland, though none have previously led to a thriving population. The presence of both male and female mosquitoes suggests that they could potentially reproduce and establish a breeding cycle.
Entomologist Jessica Ware of the American Museum of Natural History in New York City notes that humans have traveled to Iceland for millennia without documented mosquito sightings. She believes the recent appearance is likely linked to climate change, highlighting that “the fact that they didn’t [come to Iceland before], and now they are, makes me think it’s from the climate.”
Climate Change and Shifting Insect Ranges
The phenomenon of expanding insect ranges is observed worldwide, although the direct link to climate change remains unclear. The Arctic region, including Iceland, is warming at approximately four times the global average, and Iceland experienced record-breaking heat this year. C. annulata adults are known to tolerate cold conditions and overwinter in shelters like caves, basements, or barns—common in their native Europe.
The Challenges of Icelandic Winters
Icelandic winters are typically harsh, characterized by temperatures near freezing, strong winds, and heavy snowfall. However, frequent freeze-thaw cycles could pose a significant challenge to the mosquitoes’ survival. “Some species of mosquitoes are sensitive to those [temperature] fluctuations,” explains ecologist Kelsey Lyberger of Arizona State University. The success of the mosquitoes will also depend on finding a reliable food source throughout the winter months.
Potential Ecosystem Impacts
The arrival of C. annulata could trigger cascading effects within Iceland’s ecosystem. As Ware points out, these insects often serve as “climate canaries,” indicating broader environmental changes. For instance, dragonflies, which prey on mosquitoes, are likely to shift their habitat in response to changes in mosquito populations. If C. annulata establishes itself, “I wouldn’t be surprised if you start seeing [the Emperor dragonfly (Anax imperator)] and other dragonflies that have changed their ranges dramatically in other parts of northern Europe.”
The arrival of mosquitoes in Iceland offers a glimpse into the complex and interconnected nature of ecosystems in a changing climate.
Whether the newly arrived mosquitoes will survive Iceland’s winter remains an open question. However, their arrival underscores the broader trend of species expanding their ranges due to climate change and raises concerns about the potential consequences for vulnerable ecosystems worldwide.
