Scientists are making considerable strides when it comes to understanding bed bugs. What they learn will affect how pest management professionals prevent and control these pests in the not-so-distant future.
At Bed Bug University’s North American Summit in Chicago this September, researchers discussed their latest projects.
University of Kentucky. At the University of Kentucky, graduate students are exploiting molecular weaknesses in the pests. One project, led by Mark Goodman and funded by a National Science Foundation graduate fellowship, identified the bacteria bed bugs depend on to reproduce and how reproduction is affected by antibiotics.
Researchers fed one group of bed bugs a normal blood meal and another group a meal containing antibiotics. They then compared egg laying and hatch. In tetracycline-fed bed bugs, egg production and hatch dropped radically, and remained insignificant even after the pests fed on a regular blood meal.
Scientists don’t have the perfect antibiotic yet to knock out bed bugs and applying this knowledge in the field is a ways off, but the research looks promising, said Dr. Ken Haynes. “What we need is a very specific antibiotic that affects this particular bacterium.” People dealing with bed bug infestations should not take antibiotics as a means of control, as this can lead to serious health problems and resistant strains of bacteria, he cautioned.
Another University of Kentucky study led by Alvaro Romero found synergists significantly decrease the amount of insecticide required to kill resistant bed bugs. By targeting the molecular process the pests rely on to deal with environmental toxins like insecticides, Romero was able to make the insecticide more available.
Additional projects are exploring bed bug resistance to combination products, repellents and how pheromones are involved in bed bug mating.
University of Sheffield. Bed bug dispersal is the focus of ongoing research by Richard Naylor of the University of Sheffield in the United Kingdom. Bed bugs seek harborage an average maximum distance of 6.5 feet (2 meters) from the bed. Why?
In the lab, Naylor learned the pests move after feeding, spreading out among several harborages. As the population grows, bed bugs are forced to occupy harborages further from the bed. The pests disperse sooner in environments with fewer places to hide than in areas with more harborage sites. Although mating causes a high rate of mortality, female bed bugs did not disperse sooner when male bed bugs were present. The pests aren’t faithful to particular harborages, which have a “carrying capacity” perhaps regulated by humidity levels, said Naylor.
What does this mean for PMPs? Simplifying the environment with encasements and cavity fillers like caulk could force bed bugs into the periphery sooner. Naylor suggested using encasements along with passive harborage monitors to keep the pests closer to the bed, thus making the infestation easier to treat.
DNA analysis is proving what many PMPs already believed: These aren’t our grandpas’ bed bugs.
Tropical Bed Bug: Is it the Next Cimex Species to Invade the U.S.?
A sample of bed bugs from Hawaii proved that pest management professionals in the “Aloha State” aren’t just dealing with the common bed bug, but a tropical invader: Cimex hemipterus. To the untrained eye, tropical bed bugs look identical to common bed bugs, said North Carolina State University Research Associate Dr. Warren Booth, who identified the species using DNA analysis.
The sample of five adult bed bugs and 20 nymphs was provided by Orkin.
Cimex hemipterus may be the next bed bug species to invade the U.S., Booth said.
Hot, humid southern states and Mexico could provide suitable environments for the pests. Likely points of introduction include the West Coast and cities with airports flying to and from Hawaii.
Booth is unsure how widespread tropical bed bugs are in Hawaii, but doesn’t believe PMPs need to vary control techniques. Like their cousins, some of the pests are resistant to common insecticides. Tropical bed bugs can mate with common bed bugs, however, the resulting hybrids are believed to be sterile.
Several populations of tropical bed bugs have been reported in Florida, according to the Mallis Handbook of Pest Control (Tenth Edition, 2011).
Ohio State University Entomologist Dr. Susan Jones reported the pests are widespread in the warmer areas of Africa, Asia, and the tropics of North America and South America.
Tips for Dealing with Resistance. If you’ve found bed bugs aren’t responding like they should — or were — to insecticides like pyrethrin, you’re not alone. “We do have different mechanisms of resistance out there,” said University of Kentucky Entomologist Dr. Ken Haynes. He suggested pest management professionals rotate the use of products with different modes of action and use them wisely. “There’s no easy answer for this,” he said.
BedBug Central Entomologist Richard Cooper suggested moving to nonchemical alternatives, like vacuuming, steaming, freezing and heat treatment.
Will bed bugs become even more resistant in the future? It’s possible, said North Carolina State University Research Associate Dr. Warren Booth. Over the next five to 10 years he expects the number of bed bug infestations to rise and populations to inter-breed, especially in cities like New York City and Cincinnati. The resulting populations will be more genetically diverse, and genes linked to insecticide resistance could be introduced to populations once considered susceptible. Booth said controlling the pests may become “more difficult” through the increased likelihood of insecticide-resistant genes spreading.
N.C. State University. As part of an ongoing study, Dr. Warren Booth, a research associate with the Department of Entomology at North Carolina State University, tested the DNA of 66 bed bug populations in 21 states and found the pests are not from a local source but most likely came from outside the United States due to extensive human movement.
Insecticide resistance is highly prevalent in the United States, he added, with almost 90 percent of bed bug populations resistant to pyrethroids.
Low-level aggregations are highly inbred with low levels of genetic diversity, suggesting most infestations were started by a singly mated female, explained Booth. In Columbus, Ohio, however, populations showed high levels of genetic diversity from multiple sources. This is surprising given Columbus is not an international travel hot spot, he said.
Within multi-unit buildings, infestations often start with the introduction of a singly mated female or her progeny. DNA analysis of pests in a Raleigh, N.C., apartment complex proved multiple infestations were caused by a single bed bug introduction, while tests at a complex in Jersey City, N.J., showed two genetically different introductions caused widespread infestation.
Booth is expanding his research of U.S. and Canadian bed bug populations to include more than 200 populations, and also is examining populations collected internationally. (If you would like to contribute international samples for analysis, contact Booth at email@example.com.)
Prefer Heat? Make Sure You’re Fire Code Compliant
Pest management professionals using heat to zap bed bugs may be violating the National Fire Protection Code.
The code states ordinary sprinkler heads, like those used in hotels that activate between 135°F and 155°F, cannot be exposed to ceiling temperatures above 100°F. This is the temperature at which they begin to degrade. Although sprinklers may not turn on during service, their functionality could be affected, explained Massey Services Technical and Training Director Tom Jarzynka.
In addition, nothing can be placed within 18 inches of the sprinkler head or be done to impede its performance.
“PMPs using insulated covers over sprinkler heads during heat treatment are likely violating the code,” Jarzynka said.
Jarzynka spoke to fire suppression engineers, sprinkler manufacturers and local fire officials in developing Massey Services’ heat program. Due diligence was essential to ensure “we were not violating fire safety codes.” Fifty percent of the company’s bed bug service calls use heat.
Massey Services requires property managers to hire a fire suppression company to replace ordinary sprinkler heads with higher-temperature intermediate heads. When the treatment is complete, the heads are switched back to ordinary heads. This generally adds 30 percent — $250 to $350 per hotel room — to the cost of service, said Jarzynka. He said he will walk away from clients who won’t comply. “I can’t go into an environment and perform a treatment where I could be damaging the sprinkler heads,” he said.
Massey Services’ program satisfies local fire and building officials, but other markets may have different regulations. He advised PMPs to fully understand their state and local fire codes, get an understanding for how fire suppression systems work and their limitations, and design a protocol that won’t cause sprinkler heads to fail…now or some time down the road.
“Sprinklers save lives,” he reminded.
E-mail Nagro at firstname.lastname@example.org.