Three Culiseta annulata caught on a red wine rope in Kiðafell mark the first wild mosquitoes ever recorded in Iceland. What it actually tells us about climate, trade and Arctic biology — and what it doesn't.
For most of the twentieth century, an Icelandic schoolteacher could end a geography lesson with a small national boast: this country had no mosquitoes. Not because of luck. Because of arithmetic. Iceland's mild summers never gave larvae the warm weeks they needed to mature; its freeze-thaw winters drowned eggs in meltwater and froze them out again before they could hatch. The island sat alongside Antarctica in the small club of inhabited landmasses where the world's most consequential insect simply could not get a foothold.
On the night of 16 October 2025, an amateur entomologist in the valley of Kjós, twenty miles north of Reykjavík, walked out to inspect a length of rope he had soaked in red wine and hung from a tree. The wine-rope is a traditional, slightly eccentric way of attracting moths. What he found instead were three mosquitoes — two females and a male — clinging to the soaked fibres. Their identification was confirmed within days by the Icelandic Institute of Natural History as Culiseta annulata. Iceland's geography lesson now needs a footnote.
What was actually found, and what it actually means
The specimens were collected by Björn Hjaltason, a respected amateur naturalist whose moth surveys regularly contribute to the national insect record. The entomologist who confirmed the find, Matthías Alfreðsson at Náttúrufræðistofnun Íslands, the Icelandic Institute of Natural History, was unequivocal: this is the first record of wild, free-flying mosquitoes ever made on Icelandic soil.
The species matters. Culiseta annulata — the "banded mosquito" — is unfussy, cold-hardy and ubiquitous across northern Europe and the British Isles. It is not the disease-carrying tiger or yellow-fever mosquito of the public imagination. C. annulata is a nuisance biter, not a vector of any major arbovirus circulating in Europe. It is also unusually well-suited to surviving the kind of climate Iceland actually has. Unlike most temperate mosquitoes, which overwinter as eggs in pooled water, Culiseta annulata overwinters as adult females sheltering in basements, sheds, stables and outbuildings. They do not need the climate to thaw at the right moment. They need a warm cellar and an unsealed window.
That is the small, almost domestic detail that makes the finding consequential. Iceland's classic objection — "our winters will kill them" — does not apply to a species that intends to spend the winter in your boiler room.
The Icelandic Institute's preliminary view is that the three mosquitoes most likely arrived as cargo stowaways. Containers, used tyres, garden plants and ornamental flowers are the usual freight-borne pathways for Aedes and Culiseta species worldwide. Iceland's import volume has grown materially since the 2010s, and Kjós sits within commuting distance of both Keflavík airport and the country's larger industrial ports. The mosquitoes did not have to swim.
The climate signal — what is fair to say, and what isn't
It is tempting, and not entirely wrong, to read this finding as a climate story. It is also possible to overstate it.
A climate-attribution analysis cited in the international coverage notes that May temperatures over Iceland have been approximately three degrees Celsius warmer than the long-term baseline because of human-driven warming. That is a striking number — five and a half degrees Fahrenheit, applied to the most thermally constrained inhabited island in Europe. Iceland's Met Office has been logging shorter, milder winters for two decades. If anywhere in northwestern Europe was due to lose its mosquito-free status, it was Iceland.
But the honest position is more nuanced. Three specimens collected by one person on one rope in one garden in one valley do not establish a breeding population. The Institute's working assumption is that C. annulata may already be reproducing in sheltered niches near the discovery site — but the field surveys to confirm or refute that are only now being mounted. The species could, on present evidence, already be widely distributed in southern Iceland and waiting only for someone to look. Equally, the three could be the entire population — a final cohort, blown in on a freighter, that will not survive the next bad winter.
What is not in dispute is that the climate envelope that historically excluded mosquitoes from Iceland has shrunk. Whether this particular invasion sticks, another one will follow. The question has moved from "if" to "when" to "by how many species."
Iceland's previously unique status had become, in entomological circles, a slightly nervous distinction. The Icelandic Institute had been monitoring for years, in expectation of exactly this finding.
What this changes — and what it doesn't
For Icelanders, the practical implications are modest. C. annulata is a nuisance, not a public-health emergency. It bites, but it does not carry the diseases that Aedes mosquitoes carry. Bed-net manufacturers should not expect a surge of orders in Reykjavík next summer.
For the rest of us, the cultural shift is the news. For as long as it has existed, the global mosquito map has had an asterisk against Iceland. The asterisk is gone. The world's mosquito-free landmass list is now Antarctica and a handful of remote islands. That is a tidy, melancholy fact, and worth sitting with for a moment.
For science, the discovery answers a question that researchers have been quietly arguing about for a decade. Modelling suggested that Culiseta annulata could, in principle, survive in southern Iceland under mid-century warming scenarios. The finding moves that question from forecast to record. The forecast was correct; the record is now ten to twenty years ahead of schedule.
For policy, the lesson is procedural rather than dramatic. Iceland's customs and biosecurity inspection regime has been calibrated to a country that did not have mosquitoes. The Institute's recommendations to the Ministry of the Environment will, in practice, ask whether that calibration is still appropriate — particularly for second-hand tyre imports, ornamental plant shipments and the kind of low-frequency container traffic where inspection has historically been light. The answer is almost certainly that it is not. Culiseta annulata may be the species that gets in first. The next arrival is more likely to be one that matters more.
The Mosticare lens — quietly
The reason this story has travelled so far in the global press has very little to do with the specific risk posed by Culiseta annulata. It has to do with the symbolic punctuation. For thirty years, scientists have been describing climate change in graphs, ranges, probability bands and contested attribution statements. This is a story that can be told in one sentence: Iceland used to have no mosquitoes; now it has three.
The lesson for European readers further south is not to panic about Iceland. It is to take the same procedural honesty Iceland's Institute is now taking. The species moving into northern Europe in this decade — Aedes albopictus in Paris and London suburbs, Aedes japonicus in the Low Countries, established overwintering populations of Culex pipiens now infected with West Nile virus in Italy and Greece — are not insects that any of these countries dealt with thirty years ago. They are here. They are reproducing. And the institutional reflex to call them "exceptional" is itself becoming exceptional.
Three mosquitoes on a wine-soaked rope is not, in itself, an emergency. It is a moment to update the map.
What we know
- Three Culiseta annulata specimens (two females, one male) were caught by amateur entomologist Björn Hjaltason at Kiðafell in the Kjós valley, ~20 miles north of Reykjavík, on or around 16 October 2025. [Icelandic Institute of Natural History; NPR; Earth.com]
- Identification was confirmed by Matthías Alfreðsson at Náttúrufræðistofnun Íslands, the Icelandic Institute of Natural History. The Institute states this is the first record of wild, free-flying mosquitoes in Iceland.
- Culiseta annulata is cold-tolerant and overwinters as adult females sheltering in basements and outbuildings rather than as eggs in water — a biology compatible with Icelandic conditions.
- Iceland's mean May temperatures have warmed approximately 3°C (~5.4°F) above the long-term baseline, narrowing the climate envelope that historically excluded mosquitoes.
- The Institute considers freight-borne arrival (containers, tyres, ornamental plants) the most likely introduction route, with Keflavík airport and industrial ports near Kjós as plausible entry points.
- As of the discovery date, Antarctica is now the only continent on which mosquitoes are not known to be established.
Sources cited
- Icelandic Institute of Natural History (Náttúrufræðistofnun Íslands). Statement on the first record of Culiseta annulata in Iceland, October 2025. https://www.natturufraedistofnun.is/
- Phys.org. "Mosquitoes reach Iceland for the first time as the Arctic heats up." April 2026. https://phys.org/news/2026-04-mosquitoes-iceland-arctic.html
- Arctic Portal. "Iceland — a mosquito-free Arctic nation no more." https://arcticportal.org/ap-library/news/3975-iceland-a-mosquito-free-arctic-nation-no-more
- NPR. "Iceland reports the presence of mosquitoes for the first time, as climate warms." 22 October 2025. https://www.npr.org/2025/10/22/nx-s1-5582748/iceland-mosquitoes-first-time
- Earth.com. "Scientists confirm that mosquitoes are now living in Iceland for the first time ever." https://www.earth.com/news/mosquitoes-have-been-discovered-living-in-iceland-for-the-first-time-ever/