Baits: An ‘Outside-the-Box’ Bed Bug Solution

“Bed bug research” is an all-encompassing three-word description for one of the industry’s busiest and most important academic focuses of the last 10 to 15 years. While there are always research projects underway for all types of insects at entomology departments throughout the country, bed bug studies and research have dominated the conversation the past decade, just as they have in the consumer media.

The research has revolved around everything from resistance to new formulations to behavioral studies. A not-so-new research project that has been in the works for about six years could ultimately change the entire way pest management professionals treat for and prevent bed bugs.

Zachary DeVries, a doctoral student at North Carolina State University, is part of a team of researchers that includes Dr. Alvaro Romero (New Mexico State University), Angela Sierras (N.C. State University) and Dr. Coby Schal (N.C. State University), that is conducting research in an effort to create an effective bed bug bait.

Baits are common tools for fighting certain pests, such as termites, rodents, ants and cockroaches. But bed bugs have never had to circumvent a bait because the industry has been dominated by the use of pesticides, heat treatments, green or natural products, and fumigation methods.

“We wanted to think of ways that were a little different. So, we started to look at other urban pests (termites, ants, cockroaches) and the most effective and balanced tool for safety seems to be baits, where you bring the pest to the active ingredient (AI) and eliminate it using a small amount of insecticide,” DeVries said. “So, we thought of that and focused our attention on ‘What do we need to do to build a bait?’”

So, the development of a bed bug baiting system began. The benefits? Baits are easy to use; offer a long-lasting residual; target specific sites; pests are less resistant to them; and they kill using less active ingredient than other products.

Three things are needed to build a bed bug bait: an attractant, a feeding stimulant and an active ingredient.

FEEDING STIMULANT. As it relates to feeding stimulants, three questions needed to be answered by the researchers: (1) What temperature(s) induce feeding? (2) What components of human blood serve as feeding stimulants? and (3) What are the effective concentrations?

Because bed bugs readily feed on blood, the effects of blood temperature on feeding were studied. Results showed more bed bugs would feed as temperatures rose, but they did feed at every tested temperature.

Several feeding stimulants then were considered (research done by Dr. Alvaro Romero), and more than most didn’t make the cut through the trials. Glucose, albumin, globulins, vitamins, cholesterol — none worked. Then a simple component became the ideal stimulant — ATP.

Extremely low ATP levels in saline induced bed bug feeding, therefore developing a low-cost stimulant that would keep the price of the overall bait down as well. “ATP is the energy source of our bodies,” DeVries said. “All you need is that and saltwater to induce feeding in bed bugs. Dr. Romero found a lot of things that didn’t work but with ATP in saline solution he was able to induce feeding. It’s very simple and we’ve used this in many ways in our lab for other purposes.

“One of the questions we get for testing is ‘How do you leave blood in the house?’ — and this is a critical step. We would never put blood in someone’s house as part of a bait, we would just use ATP and saltwater.”

ACTIVE INGREDIENT. A variety of factors had to be considered in the search for an active ingredient that would be ideal in a bed bug baiting system. According to DeVries, bed bugs are highly resistant to pyrethroids, and ingestible insecticides work effectively on many pests and are typically used at a lower rate than most sprays.

Because bed bugs would ingest the active ingredient, the research in this area (conducted by Angela Sierras) focused specifically on which insecticides worked and what were some of the sub- lethal effects that occurred after inges-tion.

Indoxacarb, a widely used and suc-cessful insecticide for use in cockroach baiting, had little to no effect on bed bugs. Fipronil and clothianidin both were able to achieve 100 percent mortality on bed bug males and nymphs. “Angela has done a lot of screening for bed bugs and most active ingredients she’s tested are effective,” he said.

ATTRACTANT. The current stage of this project rests in this category — the search for the perfect bed bug attractant to make the baiting system ready for the industry.

“We don’t know exactly how bed bugs locate their hosts,” DeVries said. “We have to look at the choices a bed bug makes in response to CO₂, heat and body odors.”

DeVries has been able to show that bed bugs only respond to heat over a very short distance (~ 1 inch). “We’re in the process of testing odors bed bug orient towards, with the idea of identifying specific com-pounds that bed bugs are attracted to. It’s really exciting work.”

ULTIMATE GOAL. DeVries said he’s enjoyed working on this interesting, highly collaborative project. “There are several people who are working on a number of parts of this project for several years now, and we have quite a large team committed to this project.”

He said the team is out to prove the doubters wrong. “Every place we go we get skeptics, people who think it won’t work or won’t put much faith in it — it’s a long-term project and we knew it would take a long time, but we’re making great progress and learning a lot about bed bugs in the process,” he said.

“The ultimate goal is to develop a functioning bait to put out in the field but for example if we identify odors that attract bed bugs and never develop a bait, these compounds will help us to build better monitoring devices and other products.”

DeVries added, “This project combines both basic and applied research, which we can use against bed bugs to improve management. We’re excited by what we’ve found so far and the potential impact of this project on bed bug management.”

The author is a Chicago-based contributing writer who can be reached at edemask@gie.net.