A new design for a bedbug trap that uses an experimental chemical lure caught more than twice the number of bugs than a trap without the lure in a new study.

Spotting the early signs of bed bugs is one of the best ways to nip an infestation in the bud. There are a variety of methods to pick out bedbugs before they can become obvious: specially trained dogs that can sniff them out, gas chromatography to detect the airborne pheromones of bedbugs or the presence of human blood in bug poop. But these sophisticated methods are often inconclusive or expensive, or both.

Thus, “there has been continued interest in developing affordable and reliable active bed bug monitors to help detect bed bugs early and measure treatment effectiveness,” Rutgers University researchers wrote in a new paper in the Journal of Economic Entomology.

The Rutgers team wanted to improve upon existing “interceptor traps,” which are pitfall traps usually placed near a bed or under a bed or furniture leg. These traps are somewhat effective, but “passive”; they don’t attract the bugs, so where you place the interceptor trap is a bit of a gamble.

Their new trap, designed to more actively draw bedbugs out, is a mixture of high-tech and low-tech. The scientists used a dog bowl from IKEA (turned upside-down) to create a pit for the bugs to fall into. The outside of the dog bowl was wrapped in black electric tape, and the inside was coated in a resin to keep trapped bugs from escaping. Then they pitted their design against commercial interceptors in a series of trials.

The new trap design turned out to be much more effective than the existing commercial option, the Climbup insect interceptor trap, catching 2.8 times as many bugs. The researchers speculate this is because their trap is deeper and thus, harder to escape.

However, ordinary interceptor traps can be even more effective with the addition of any one of the primary bedbug attractants: carbon dioxide, chemical lures, or heat, the team found.

In some trials, the scientists tested the efficacy of a bedbug lure made from a cocktail of chemicals: spearment oil, coriander Egyptian oil, nonanal, and 1-octen-3-ol. The latter two chemicals can be synthesized, but are also produced by the human body. Other trials examined the effectiveness of attracting bedbugs using a sugar-yeast mixture to generate carbon dioxide, or carbon dioxide fed directly from cylinders.

Chemical lures significantly improved the performance of the interceptor traps. Baited traps caught 2.2 times as many bedbugs as the unbaited one. Traps baited with carbon dioxide also caught more bugs than unbaited traps, and there was no significant difference in the attractiveness between carbon dioxide baits derived from a sugar-yeast mixture and those that used carbon dioxide cylinders.

Adding chemical lures, carbon dioxide, or heat to a deeper trap could be key to catching more bedbugs, the scientists say.

“This trap can be placed anywhere inside the home to detect bed bug infestations, to determine the distributions of bed bugs in an infested dwelling, and to measure treatment results,” the authors wrote. “This monitor may also be combined with insecticides to attract and kill bed bugs that are attracted to the monitor.”

SOURCE: Singh et al. “Effect of Trap Design, Chemical Lure, Carbon Dioxide Release Rate, and Source of Carbon Dioxide on Efficacy of Bed Bug Monitors.” Journal of Economic Entomology 106: 1802-1811, 6 August 2013.

RELATED STORIES