The so-called London Underground mosquito was long thought to be an example of modern or observable evolution [Getty]
A mosquito long thought to have evolved in the tunnels of the London Underground actually originated more than a thousand years ago in the ancient irrigation systems of Egypt, according to new genetic research.
The study overturns decades of scientific belief that the so-called “London Underground mosquito” – Culex pipiens form molestus – emerged recently beneath Britain’s capital.
For years, it had been widely cited in textbooks and documentaries as an example of “modern evolution”, a species adapting rapidly to a man-made environment.
Researchers from the Wellcome Sanger Institute and the Natural History Museum have now found that the insect’s distinctive underground traits pre-date both London and the Industrial Revolution.
Published in Science, the study compared DNA from hundreds of mosquito samples, including historical specimens from the Natural History Museum’s collection. The results show that the underground form diverged from its surface-dwelling relatives between 1,000 and 10,000 years ago. The oldest and most genetically diverse populations were traced to the Mediterranean basin – particularly Egypt.
Dr Mara Lawniczak, senior group leader at the Wellcome Sanger Institute and co-author of the study, said the findings prove the mosquito’s evolution happened long before London’s tunnels were built.
“These genomic data from old specimens helped confirm that the notorious London Underground mosquito is a form that evolved long ago, way before underground human transportation existed at all,” she said.
Lead author Dr Yuki Haba said the research points to an origin in early agricultural societies. “Our analyses strongly suggest that molestus first evolved to bite and live alongside humans in an early agricultural society 1,000 to 10,000 years ago, most likely in Ancient Egypt,” he said.
The mosquito’s defining characteristics – its preference for human blood, its ability to breed year-round and its lack of winter hibernation – appear to have developed amid early human settlements, where enclosed, humid spaces provided ideal conditions.
Those same traits later allowed it to colonise modern underground environments, including London’s rail system.
The myth of the “London Underground mosquito” took hold during the Second World War, when people sheltering in Tube stations reported being bitten in the dark. Combined with later studies suggesting isolated tunnel populations, the story of a newly evolved urban species took root.
Scientists now believe that rather than a recent adaptation, the insect’s success reflects a much older relationship with human civilisation – because molestus can interbreed with its bird-biting relatives, it also serves as a potential bridge for diseases such as West Nile virus to pass from birds to humans.
Far from being a quirk of modern London, the mosquito’s story begins in the ancient world – a survivor of the first great irrigation networks in the history of human civilisation in Egypt’s Nile Valley.Â
