Iceland no longer mosquito-free, first sighting confirmed!
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Take your experience further with Premium access. Thought-provoking Opinions, Expert Analysis, In-depth Insights and other Member Only BenefitsA citizen of Iceland sighted mosquitoes at his home last week and sent photographs for confirmation — a scientist has confirmed this as the country's first instance of the insects, though further monitoring is needed to determine if the species has established itself.
The presence of the mosquitoes could suggest a recent introduction, possibly transported via ships or shipping containers, said Matthias Alfredsson, an entomologist at the National Science Institute of Iceland.
While the species, identified to be a 'Culiseta annualata', may be habituated to cold climates, warmer conditions driven by global warming could make it easier for the mosquitoes to survive and establish themselves here, Alfredsson said.
Culiseta annualata, or Cs. annulata, naturally occurs in northern regions of Europe and can withstand freezing temperatures, he said.
Studies have shown that with ongoing global warming, conditions such as high humidity and rainfall can make the environment conducive for mosquitoes to breed, thereby enabling infectious mosquito-borne diseases to spread into regions that previously recorded few cases.
Iceland remains one of the few mosquito-naive places on the planet, with another being Antarctica.
"Since 2019, Bjorn Hjaltason (an insect enthusiast) has been experimenting with a method known as wine roping, a technique used to attract moths," Alfredsson described.
The method involves soaking a long cloth in a sweet, fermenting mixture of red wine and sugar, the odour of which draws moths.
"On the evening of October 16th, Bjorn found something unexpected on his wine ropes, an insect he initially thought was a mosquito. He sent me a photograph, and upon closer inspection, it was confirmed to be a female mosquito," he said.
Alfredsson visited Hjaltason's home the following day, where he then found a male specimen. The day after, a female was also found.
From the start, it was clear that the insects belonged to the genus Culiseta. After going through identification keys, the species name was confirmed, Culiseta annualata," the entomologist said.
Identification keys are scientific tools used to determine the species of an organism. They consist of a series of paired, contrasting statements describing organism's observable traits, which are analysed for arriving at a conclusion.
Alfredsson explained, "This mosquito species appears to be well adapted to cold climates, primarily due to its ability to overwinter (spend the winter) as adults in sheltered places." "This enables them to withstand long and harsh winters at a freezing temperature," he said and added that the species also uses a diverse breeding habitats, further enhancing its ability to persist in Iceland.
"Its presence may indicate a recent introduction to the country, possibly via ships or containers," the entomologist said.
He added that while Cs. annulata is a cold-tolerant species, a warming climate could still make it easier for the species to survive and establish in Iceland.
"Milder winters and longer frost-free periods may increase the chances that individuals arriving here can complete their life cycle successfully," Alfredsson said. "So although this particular finding is not necessarily a direct result of climate change, a gradually warmer climate could make Iceland more hospitable to a wider range of insect species in the future," he said.
The next steps include monitoring the area around Hjaltason's home to determine whether the species has formed a breeding population and to check for additional mosquitoes in the next spring or summer.
"All specimens (retrieved from Hjaltason's home) are stored in my freezer and will be preserved as a part of the scientific collection at the Natural Science Institute of Iceland," Alfredsson said.