In an unexpected holiday season gift, researchers at Simon Fraser University announced they may have finally cracked the chemical code of bed bugs. In field trials, their blend of bed bug attractant caught 100 percent of bed bugs.
Even better? The total chemical cost of the synthetic chemicals used in the trap was 10 cents. A cheap, effective way to monitor and control bed bugs may finally be in reach.
Gries et al. 2014. Bed Bug Aggregation Pheromone Finally Identified. Angewandte Chemie DOI: 10.1002/anie.201409890
Bed bugs have a distinct odor, although just what they smell like varies depending on who you ask. Personally, I think they smell like Crayola crayons; others have described them as "new car smell." That scent is part of a complex chemical brew that signals other bed bugs to gather round.
As early as the 1970's scientists knew that bed bugs were attracted to bed bug feces and shed exoskeletons. In 2008 some components of the chemical that attracted other bed bugs were described. This kicked off a Great Pheromone Race in bed bug research. Pheromones are chemicals released by animals to communicate with other members of their species; they are successfully used in trapping lots of different insects. Because pheromones are species specific, and occur at very low concentrations (µg or micrograms), they are safe for consumers to handle and use without any special training or precautions.
If humans could manufacture the chemical bed bugs use to signal and attract each other, we could use it to call bugs to a spot so we could count them...and then kill them.
The missing piece of the bed bug blend has finally been identified, and the reason it took so long is that it isn't a smell. The last component is sensed by bed bugs only upon contact. Histamine, the same chemical produced by our white blood cells as part of the human immune response, acts as an 'arrestant' in combination with the other chemical blend. It makes the bed bugs stop walking and nestle in.
Once the Simon Fraser University research team added histamine to their traps, everything changed. Traps baited with their blend caught all types of bed bugs: nymphs and adults; males and females; and both fed and unfed bed bugs.
Now we have a quick, inexpensive way to monitor and find new infestations, one of the most difficult parts of preventing bed bugs. Because the trap attracts and catches bed bugs, it should help prevent new infestations by luring in any wayward bed bugs that traveled home with you on your suitcase.
It's expected traps using this new blend might be on the market for purchase by consumers in late 2015.
Known Unknowns
This could be a real turning point in the war on bed bugs. I am optimistic that this new development will significantly improve our ability to detect bedbugs and kill them.
I also think it's too early to declare victory.
Bed bugs are living animal, and anytime you change an organism's environment, the potential for evolution of resistance to a control method exists. Pheromones can be tricky to work with, because they function differently at different population densities.
In low populations of bed bugs, an aggregation signal is a great idea. "Hey! Over Here!" signals new arrivals to come and hang out in a safe refuge. Bed bugs grow faster in a group than alone. They also save moisture by gathering together; low humidity is a problem in heated homes.
But in crowded conditions, things are uncomfortable. Females are besieged by males looking for a hookup. The traumatic sex life of bed bugs is the stuff of nightmares. Males use a stabby-cock-dagger to just grab and inject females with sperm directly through their body wall. That is just as uncomfortable as it sounds, not to mention the stabby male penis is covered with germs.
In crowded conditions, female bed bugs tend to wander off. So, while this new research is going to be very helpful in preventing new infestations, and controlling small ones, it isn't going to be a control method for heavily infested buildings. It might even make things worse in that situation, by encouraging dispersal of egg-laden females.
For most of us, though, this is great news. While we can't wipe bed bugs out---and that's not a realistic expectation anyway---we do have a great new tool in our armamentarium.
