“The last mosquito that bit me had to check into the Betty Ford clinic.” — Patsy, Absolutely Fabulous

In A Nutshell

The London Underground is a sprawling subway network that runs underneath one of the busiest cities in the world. However, among the one billion commuters who use the service each year, there’s another species occupying these tunnels. Classified as Culex pipiens f. molestus, this is a species of mosquito that has specially adapted to the conditions of the tunnels and now happily spends its days attacking passengers and staff alike.

The Whole Bushel

It’s no surprise to hear that the London Underground has a problem with pests. After all, it’s an underground network of warm, dark tunnels underneath one of the busiest cities in the world. However, among the rats and the bats that occupy this vast maze, another menace stalks the tunnels. This creature is Culex pipiens f. molestus, also known as the “London Underground mosquito.”

First reported in a 1999 research paper by geneticists Kate Byrne and Richard Nichols—a paper entitled “Culex pipiens in London Underground Tunnels: Differentiation Between Surface and Subterranean Populations”—this species of mosquito is unique to the London Underground, having adapted its biology to survive and thrive within this harsh subterranean environment.

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Mosquitoes require pools of stagnant water to lay eggs, which aren’t uncommon in the tunnels. However, as a result of the millions of people who use the transportation network each day, these puddles also contain a relatively high amount of nutrients, derived from organic material such as discarded sandwiches and human skin cells. By laying eggs in this water, mother mosquitoes have ensured that each of their children will be a large and healthy specimen. Indeed, such is the power of this water that the mothers don’t need to enjoy a nutrient-rich blood meal before laying their eggs.

While this species was only acknowledged in 1999, there’s evidence that they’ve been around since the 1800s, after their ancestors colonized the network while it was under construction. Indeed, it was widely reported that the Londoners who used the tunnels to shelter from the Blitz during World War II were attacked regularly by these creatures. Even more recently (and worryingly), specimens of this mosquito were found within the New York subway system in 2011, but only after they started infesting houses built on top of the subway lines.

Show Me The Proof

“Culex pipiens in London Underground tunnels: differentiation between surface and subterranean populations,” Katharine Byrne and Richard A Nichols

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