Humans were letting the bed bugs bite long before beds existed, and while they do live on other species, we’re the main reason this notorious parasite is still going strong.
In fact, bed bugs might have been the first pest to plague our cities – earlier than the black rat, for instance, which joined us in urban life about 15,000 years ago, and even the German cockroach, which only got the memo about 2,100 years ago.
Researchers think the blood-sucking pests – Cimex lectularius – first jumped from their bat hosts onto a passing human some 50,000 years ago, a move which would change the course of the insect species forever.
Human bed bugs, it turns out, have boomed since the Last Glacial Maximum about 20,000 years ago. But it’s a different story for those populations that continued living on bats.
“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,” says entomologist Lindsay Miles, from Virginia Tech.
“The really exciting part is that the human-associated lineage did recover and their effective population increased.”
The researchers were able to track this evolution because the human bed bugs have a much narrower genetic diversity, since only a few ‘founders’ probably came with us when we abandoned life in caves. But our move into cities around 12,000 years ago is what really kicked off the human bed bug boom.
This was only briefly interrupted when DDT was invented in the 1940s. Populations crashed, humans slept sweetly, and then five years later, the bed bugs were back.
Since then, bed bugs have travelled around the world with us, and even become resistant to our pesticides. For now, it seems, bed bugs are here to stay. It’s been a long-term relationship, after all.
The research is published in Biology Letters.
