SFU re­searchers de­velop fiendish mouse, rat trap

Us­ing bevy of scents shows dra­mat­i­cally in­creased cap­ture rates com­pared to clas­sic de­signs

The Province - - FRONT PAGE - RANDY SHORE rshore@post­media.com

Re­searchers at Si­mon Fraser Univer­sity have de­vised a fiendishly clever way to trick rats into get­ting inside a trap by ex­ploit­ing their snack­ing pref­er­ences, the com­fort of com­mu­nity, the prom­ise of sexy fun time and even the cries of baby ro­dents to play on a mother’s in­stincts.

An­i­mal com­mu­ni­ca­tion ex­pert Ger­hard Gries started by cre­at­ing a food odor­ant that mim­ics a smor­gas­bord of cheese, hazel­nuts, choco­late, fresh meat and other rat favourites.

That was ef­fec­tive — cer­tainly bet­ter than com­mer­cially avail­able at­trac­tants — but rats are nat­u­rally wary of new ob­jects and even the prom­ise of a tasty meal isn’t al­ways enough to lure them in.

So Gries added pheromones and steroids, such as male testos­terone or fe­male pro­ges­terone and estra­diol to let the rats know that, A) there is an­other rat inside, so it’s not that dan­ger­ous and, B) maybe you’ll get lucky if you go inside. The fe­male blend in­creased cap­tures of male mice eight-fold and male rats 13-fold, while syn­thetic testos­terone in­creased cap­tures of adult fe­male mice 15-fold.

“We were pleas­antly sur­prised, it’s an amaz­ing in­crease in bait at­trac­tive­ness,” said Gries, who is de­vel­op­ing sys­tems ef­fec­tive on Nor­way rats and house mice. Those re­sults were pub­lished in the jour­nal ChemBioChem.

But Gries wasn’t quite done. To re­ally seal the deal for the most wary ro­dents, his team recorded the ul­tra­sonic squeaks of baby ro­dents and played them back inside the trap. The record­ing quadru­pled the catch rate over even the com­bined food and pheromone baits.

“We think the fe­male rats are go­ing in to check on the ba­bies and for the male rats, if they aren’t his ba­bies, he would eat them like a juicy steak,” he said.

The lab’s re­sults have at­tracted at­ten­tion from pest-con­trol firms all over the world and the tech­nol­ogy prom­ises to be ex­tremely af­ford­able. Pheromone-based in­sect traps can be bought for less than $10.

Gries is de­ter­mined to re­place poi­son­ing as a means of pest con­trol to re­duce the risk that poi­son-filled ro­dents will lead to sec­ondary poi­son­ings of preda­tors such as coy­otes, foxes and birds.

Lo­cal rats are most likely to carry lep­tospira, a bac­terium car­ried in rat urine that causes fever in hu­mans, though the bubonic plague has re­cently spread across Mada­gas­car, ac­cord­ing to Kaylee By­ers, a PhD stu­dent at the Univer­sity of B.C. do­ing re­search at The Van­cou­ver Rat Project.

Rats are a for­eign, in­va­sive species from Asia, but they thrive in Van­cou­ver.

“Anec­do­tally, it seems as though we’ve had a rise in our rat pop­u­la­tion over the past few years ... pest-con­trol pro­fes­sion­als say they are get­ting more calls,” she said. “But re­ally, we have no idea.”


Re­searchers at SFU, in­clud­ing Ger­hard Gries, have de­vel­oped a phe­nom­e­nally ef­fec­tive at­trac­tant for rats and mice.


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