If you live in a big city, you're probably familiar — a little too familiar, perhaps — with bedbugs.
As their name suggests, they start by infesting the places we sleep.
Within weeks, the blood-sucking creatures have turned an entire apartment into an itchy nightmare.
Bedbugs didn't always used to be the terrifying critters we know today. For decades, we lived in peace, undisturbed by these tiny creatures of the night.
But bedbugs are back.
To Brooke Borel, the author of the new book "Infested," the recent return of bedbugs is part of a growing trend in which the things we try to eradicate come back, oftentimes with a vengeance.
The return of bed bugs, Borel writes, "isn't a fluke. It is a return to normal."
From cave to city
Thousands of years ago, our cave-dwelling ancestors got along perfectly fine with bedbugs. Back then, they were nearly an entirely different species.
As humans migrated out of caves and into cities, a process which took us thousands of years, we brought bedbugs along for the ride. Not surprisingly, the bugs with traits that made them better able to survive in their new digs outlived their friends and family members who weren't as well suited for the urban lifestyle.
These new bugs were more active at night, when humans sleep, and had longer, thinner legs for hopping away from us quickly.
But bedbugs' evolution is hardly a finished story. They're still evolving, and in the last few decades they've developed perhaps their worst trait of all: Resistance to bug poison.
Unbeatable bugs
The bedbugs of today have thicker, waxier exoskeletons, which helps shield them from the insecticides we try to poison them with, and faster metabolisms to beef-up their natural chemical defenses.
As a result, many scientists are searching for a new way to make them disappear.
Biologist Regine Gries of Simon Fraser University, for example, spent the better part of the last five years spending the night in a bedbug-infested lab. She and her team recently found the basic ingredients for a bug-alluring scent that people could potentially use to trap bed bugs.
Scientists still aren't entirely sure why bedbugs have only now started to come back so strongly, Borel writes, but people are playing an important role in their recent return.
During World War II, scientists discovered the insecticide DDT. With this poison, they succeeded in wiping out tons of insects, including bedbugs, Borel writes. But recently, it stopped working.
Here's Borel:
People used these pesticides for bed bugs in regions outside of the United States where the pest was still common, and also inadvertently dosed the bugs while treating for other insects. Bed bug insecticide resistance grew, for example, in malaria-ridden parts of Africa and Central America as the World Health Organization tried to curb mosquitoes by treating homes with DDT. All it would take for the bed bug to roar back would be a way for it to spread from those resistant hotspots to the rest of the world.
International travel provided that window for the bedbug, Borel writes. As the critters hitched a ride on everything from shoe soles to infested luggage, they spread across the globe. Today, they're an international scourge.
"In a way, we created the modern bed bug: it evolved to live on us and to follow us," Borel writes.
Just what we'll do about the critters remains to be seen.
