Eric Siljander

They're baaaack: Eric Siljander inspects a tray of common bedbugs in the lab. Once they “fell off the radar," says the recent Master of Pest Management grad, "no work was really done trying to identify things that would attract them until now.”

Biologist baits bloodsuckers

October 4, 2007

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Stuart Colcleugh

Eric Siljander spent the past three years investigating nasty little creatures that slip silently beneath bed sheets in the black of night to feast on human blood and then disappear into the darkness.

Once considered virtually eliminated in industrialized countries, the common bedbug—Cimex lectularius—is back with a vengeance. But the Coquitlam native, who convocates this month with a master’s degree in pest management, has identified and tested a pheromone that lures bedbugs from their hiding places.

And the discovery comes none too soon. Cities around the world have recently witnessed an explosion of bedbug infestations, and not just in hostels and low-income housing but also in expensive hotels and luxury penthouses, affecting people in every tax bracket.

The pests don’t transmit diseases, but they are extremely difficult to exterminate. Their resurgence has been attributed to everything from increased international travel to a limited arsenal of effective pesticides and a ban on more powerful pesticides such as DDT in the early 1970s.

What’s more, says Siljander, once bedbugs “fell off the radar, no work was really done trying to identify things that would attract them until now.” And attraction is the key—both to early detection and to confirmation that the insects have been completely exterminated from a treated location.

Working with SFU insect communication ecologist Gerhard Gries, Siljander set out to find the pheromone, or communication chemical, that the half-centimetre bloodsuckers use to congregate.

“Bedbugs are a gregarious species,” explains Siljander, “and they will often group together. So my goal was to identify the pheromones they’re using to find each other.”

In experiments using olfactometers, which measure an insect’s behavioural response to odors, and gas chromatography-mass spectrometry he found ‘contact pheromones’ left by bedbugs on absorbent paper discs and analyzed airborne chemicals collected from colony jars, identifying 14 different candidate pheromone components.

From those components, he isolated the pheromone that makes bedbugs come running—to shelters baited with the chemicals. The next step will be to field-test the pheromone lure’s effectiveness in actual infested locations.

But Siljander is already on the trail of other pest menaces. “I’m looking to work with the Canadian Food Inspection Agency,” he says, “hopefully to deal with invasive species like gypsy moths.
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