Though they’re the cause of many recent nightmares, bedbugs have been keeping people awake at night for thousands of years. Archeologists in Egypt once found a 3,500-year-old fossilized specimen of the skin-crawling parasite. There are also writings from ancient Greece and Rome that mention the bloodsuckers.
Now, a paper recently published in the journal Molecular Ecology has zeroed in on just where bedbugs first came from. The research “provides the first genetic evidence that bats were the ancestral host of the bed bugs that plague human residences today,” reports Melissa Hogenboom over at BBC Earth.
Scientists have previously suspected that bats were responsible for introducing bedbugs to the human population, back when the two species both made caves their home: bats are known to be plagued by their own member of the bedbug family. The new research, co-authored by Dr. Warren Booth of the University of Tulsa, appears to confirm this theory. It also determines that the two parasites feeding on bats and humans respectively have evolved into two separate lineages without much interchange.
Booth's team sampled hundreds of bed bugs from human and bat dwellings from 13 countries around Europe.
An analysis of their DNA showed that there was no gene flow occurring between the human and bat bed bugs, even though some bats lived in churches or attics and could therefore have come into human contact.
Bat bugs, as they are colloquially referred to, are fairly common to North America but typically only bother humans when their animal hosts have fled. Booth told BBC Earth that bat bugs are more genetically diverse and are so different from the human-feeding kind that, when interbred, “the offspring were less fertile.”
Bedbug populations are resurging in many parts of the world after decades of near-eradication. That’s in part because the parasites have developed a resistance to the pesticides used to rid them from our homes and hotel rooms beginning in the 1950s. According to data collected by Orkin and cited by Time, the business around getting rid of bedbugs increased 18 percent last year, and in 2013, Americans spent $446 million on the effort.
There’s some good news, though: despite being gross and ruining property, bedbugs have not been shown to transmit diseases. But perhaps that knowledge won’t keep you from checking your mattress before getting into bed tonight.