“They’re more of a nest insect,” said Bill Donahue, entomologist and owner of Sierra Research Laboratories in Modesto, where he evaluates treatments for bed bugs and other pests. “There are areas where the bed bugs will congregate.”
A group of young bed bugs known as nymphs live close together in a nest. Empty egg shells are visible in the upper left corner. (Josh Cassidy / KQED)
Adult bed bugs are about the size and color of an apple seed. Young beetles, called nymphs, are smaller and yellowish or white. Guided by the carbon dioxide and warmth that sleeping people give off, they quickly crawl on wooden bed posts and over sheets to stick their long mouth parts in and drink for about five minutes until they are completely full. They then hide in a nearby nook, like the seam of the mattress or behind a baseboard.
“Heaven forbids you to wake up with itchy red welts during your stay,” said Potter. “Then you want to be incredibly vigilant when you get home.”
An adult bed bug feeds on a human thumb. (Josh Cassidy / KQED)
He suggests putting clothes in the dryer or leaving unpacked suitcases in a hot car, as bed bugs are prone to high temperatures. Some people take days or even weeks to respond to a bed bug bite. Hence, bites are not a good indicator of when you’ve been exposed to them. And while some people can experience a severe skin reaction, bed bugs are not known to transmit disease.
The body of an adult bed bug is elongated after being fed with a human arm. Bed bugs need a blood meal to molt and grow to each of their five life stages. (Josh Cassidy / KQED)
Bed bugs were widespread in the United States until the 1940s. After being nearly wiped out by DDT spraying in the 1950s, they have made a comeback worldwide in the past 20 years, aided by the widespread movement of people. According to Potter, they have been found across the country in settings as diverse as schools, dormitories, hospitals, theaters, moving trucks and even funeral homes. And they move on used furniture too.
Residents are more prone to infestation as insects can crawl from one apartment to another. Because bed bugs hide, they are difficult to treat without the help of a professional, which can be expensive.
An adult bed bug crawls up a bed post. (Josh Cassidy / KQED)
“If you think you have bed bugs, let your landlord know right away,” said entomologist Andrew Sutherland, the University of California’s pest control advisor in the San Francisco Bay Area. “It is your responsibility to conduct inspections and have a reputable pest control operator deal with the problem.”
Because bed bugs are prone to heat, heat treatment is “the gold standard,” said Luis Agurto, CEO of Pestec, a pest control company in the San Francisco Bay Area. Pestec sets up large heaters in an infested residence and heats them to 122 degrees for two hours. Technicians armed with “guns” blow hot air into areas where bed bugs may be hiding.
“We’re basically making a big fan oven,” said Agurto.
After heat treatment, Pestec monitors bed bugs for several weeks by placing a hard plastic cup under each bed post. The insects have no problem climbing up the rough outside of these so-called catching cups, but are then caught by the smooth inside, which they cannot scale. The company also uses insecticides and vacuum cleaners to clean up the infestation.
A bed bug is trapped in a catcher under a bed post. Bed bugs can crawl into these plastic cups, which have a rough outside but cannot climb onto the smooth inside surface. (Josh Cassidy / KQED)
Pestec was hired to investigate and treat infestations from just six bed bugs in an apartment in San Francisco’s Haight neighborhood to a townhouse in a residential complex in Potrero Hill that had insects “on all surfaces”. Said Agurto.
Scientists are working to find more tools to get rid of bed bugs. At UC Irvine, biologist and engineer Catherine Loudon works with several technical laboratories on campus to create synthetic surfaces that can trap bed bugs. It was inspired by the tiny hook hairs that grow from the leaves of some types of beans, such as kidneys and green beans. In nature, the hairs stick through the feet of aphids and cicadas, which like to feed on them.
A bed bug broke loose in Catherine Loudon’s lab at UC Irvine after her front left foot was pierced by a tiny hook hair on a kidney bean leaf. (Josh Cassidy / KQED)
Loudon got the idea from Potter at the University of Kentucky, who mentioned a folk remedy he had read about. Balkan residents were spreading bean leaves around their beds, and in the morning they found bed bugs clinging to them. It turned out that the bed bugs’ feet were impaled by the hook hairs on the bean leaves called trichomes. Researchers have found that trichomes are just as effective against bed bugs, despite not feeding on leaves.
Kidney and green beans, as well as other types of beans, have tiny hook hairs on their leaves. These trichomes help the plant protect itself from leaf-eating pests such as aphids, but they also trap blood-sucking bed bugs. (Catherine Loudon / University of California, Irvine)
A trichome pierced the soft joint of a bed bug foot. (Catherine Loudon / University of California, Irvine)
Loudon’s goal is to mimic the mechanism of a bean leaf to create an inexpensive, portable trap.
A bed bug caught by a tiny hook on a synthetic surface that mimics a bean leaf. This surface was produced at UC Irvine in the laboratory of engineer Allon Hochbaum. (Catherine Loudon / University of California, Irvine)
“You can think of a strip that acts as a barrier and can be placed just about anywhere: across the portal to a room, behind the headboard, on subway seats, on an airplane,” said Loudon. “You have six legs, so there are six ways to get caught.”