Before Roaches, There Were Bed Bugs–And They Followed Humans Into The First Cities

Bed bugs have been bothering humans since the first cities were established. According to a new study, they are likely the first real urban pest.

Bed bugs on bed
Bed bugs have thrived in cities since they were first established.


Bugs rule the world. They make up approximately 90% of animal species on earth, with an estimated 1.4 billion insects for every living human. From bees to butterflies to cockroaches and ants, humans interact with these insects all the time. And sometimes they can only be described as pests. A new study published in the journal Biology Letters now shows that humanity's first real urban pest was likely the creepy, blood-sucking bed bug.

Bed Bugs Followed Neanderthals From Caves To Cities

Bed bugs have been around for over 100 million years. They survived the extinction of the dinosaurs and have been feeding on animals and humans ever since.

60 000 or so years ago, Neanderthals journeyed out of their caves. And some of the bed bugs that had been living with them made the journey too, jumping from bats (their favourite host at the time) to early humans.

Bed bug larvae
Bed bugs split into two genetic lines, one that fed on humans and one that fed on bats.

Now, research shows two very distinct genetic lineages of bed bugs (Cimex lectularius) exist. The one that stayed with the bats, and the one that chose to start preying on humans. Since the last glacial maximum about 20 000 years ago, the bat-loving bed bugs have had a population decline.

Meanwhile, the ones that made the humans their prey have thrived since humans started living in cities such as Mesopotamia around 12 000 years ago.


“Initially with both populations, we saw a general decline that is consistent with the Last Glacial Maximum; the bat-associated lineage never bounced back, and it is still decreasing in size,” said Lindsay Miles, lead author of the study, in a press release. “The really exciting part is that the human-associated lineage did recover and their effective population increased.”

Using This To Inform Future Pest-Human Relationships

The researchers now have a foundation to study the genetic lineages of both the human and bat-associated bed bugs. They have already discovered a gene mutation that could contribute to the insecticide resistance found in bed bugs and want to further investigate this.

“What will be interesting is to look at what’s happening in the last 100 to 120 years,” said Warren Booth, one of the authors of the study. “Bed bugs were pretty common in the old world, but once DDT [dichloro-diphenyl-trichloroethane] was introduced for pest control, populations crashed. They were thought to have been essentially eradicated, but within five years, they started reappearing and were resisting the pesticide.”

Bed bugs look to be the first true urban pest, and they continue to bug humans to this day.

News Reference

Were bed bugs the first urban pest insect? Genome-wide patterns of bed bug demography mirror global human expansion. Biology Letters. May 28, 2025.

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