Overview
- A Science study dated Oct. 23 finds Culex pipiens f. molestus split from bird-biting pipiens roughly 1,300–12,500 years ago in the Mediterranean or Middle East, overturning the London Underground origin story.
- Researchers analyzed whole genomes from 357 mosquitoes collected at 77 sites across western Eurasia, supported by DNA from historic Natural History Museum specimens in London.
- Evidence suggests early agricultural irrigation and stored water provided year‑round breeding sites that fostered human-associated traits long before modern subways existed.
- Molestus shows adaptations for subterranean life—biting mammals, mating in confined spaces, staying active in winter, and laying eggs without a blood meal—traits that later thrived in urban belowground habitats.
- Hybridization with pipiens appears less common than assumed but occurs in large cities, prompting calls for targeted sampling to clarify gene flow, biting behavior, and West Nile virus spillover risk.