Learning The Language Of Bugs

By Desiree Willis

They're everywhere. Scuttling underfoot, buzzing around your head, busily hustling through the day like traffic on a freeway. And, not unlike humans, they are constantly talking to each other.

Insects employ many modes of communication, including scent and sound. These species-specific messages are carried through the air and received by those who know the local language.

Understanding insect communication is crucial in developing new technologies to fight pests, and Gerhard Gries, professor of biological sciences at Simon Fraser University (SFU) in Burnaby, B.C., is learning to talk with them.

In February 2005, Gries was awarded a grant of $2.5 million from the Natural Sciences and Engineering Research Council (NSERC) and was appointed to an Industrial Research Chair (IRC). Gries' new IRC position allows him to coordinate with industry in the development of safe alternatives to chemical pesticides.

"We can study complex communication of insects, and then utilize our acquired knowledge,” says Gries. His research involves studying complicated compounds called pheromones. These compounds are emitted into the air as scents and are picked up by other insects. The scent cues are used for everything from mating rituals to species identification.

Gries utilizes these scent signals to lure pests into traps. Previous research used pheromone technology as pest control, but Gries' research uses a novel method. In the past, most companies have concentrated on trapping or disorienting adult insects, says Gries. His research on some species concentrates on larvae.

In the case of Coddling Moth, a universal agricultural pest, larvae secrete a pheromone that causes them to aggregate in one spot. This increases their chance of survival. By using cardboard traps impregnated with the aggregation compound, Gries and his team are able to capture a large number of the larvae.

All of this is important for several reasons. First of all, Gries' cardboard traps are cost effective, and the chemicals can be synthesized cheaply compared to conventional pesticides. In addition, these "organic pesticides" carry no human health concerns compared to their conventional counterparts. Conventional pesticide residues have been linked to cancer and many kill off beneficial insects as well as harmful ones.

But Gries is going one step further with his insect language research: he is creating bait equivalent to the actual allure of an adult female. Utilizing several modes of insect communication, he is creating bait of unprecedented efficacy.

Gries has targeted the Peach Twig Borer Moth. Each year, millions of peach fruits and trees are damaged by the insect. Gries is using bioacoustic signals emitted by insects. When combined with pheromones, the traps are as effective as baiting traps with actual adult female moths.

"Insects use multiple modalities,” says Gries. "As humans, we can see and hear. Insects also have sound and scent.” In Peach Twig Borer Moths, the male calls to the female, and the female answers back. This cue allows the insects to locate each other.

By mimicking the female's call, males can be trapped or disoriented. In addition, females can be targeted as well. The call of the male induces a female to lower her pheromone signals because she assumes that a male is nearby. Gries will use mimicked male calls from microchips implanted on trees to induce females to lower their pheromone output. With few scent signals to go on, males can't find females of their own species.

The net effect of Gries' virtual insects is that fewer individuals mate, and therefore successive generations of the insect will be smaller. It is Gries' partnerships with industry, however, that are allowing his innovations to become commercial enterprises.

Gries' IRC Chair facilitates a close partnership with organizations such as SC Johnson & Son, Phero Tech, Inc., and the Western Grains Research Foundation. These organizations along with Global Forest, a nonprofit, are working with Gries and his team on various projects.

John Borden, director of research and development at Phero Tech, Inc. in Delta, B.C., says that Gries' research is valuable and novel because of its species specificity. The pheromone-baited traps are compatible with other control measures, such as conventional and microbial pesticides.

However, cautions Borden, "Any time you take an insect out of its ecosystem, you affect that ecosystem.” Gries' insect traps may still have implications for the surrounding environment. But, says Borden, "all pest control has effects on the ecosystem.”

Borden still believes that Gries' research holds enormous potential because it could have a smaller effect on ecosystems than conventional pesticides. This makes Gries' pheromone and acoustic traps applicable in wide areas of pest control.

Phero Tech and SC Johnson & Son are currently working with Gries to develop new technologies for control of urban pests, such as house spiders, flies, and bedbugs.

"It's a win-win-win situation,” says Gries of his IRC chair. Private citizens win because they gain a safer way to get rid of insects in their homes and gardens, he says. Industry wins because they have a product to market, and some of that profit goes back to research.

The industries Gries works with do not control the scope of his projects, however. Companies like Phero Tech Inc. meet with Gries and fund his research, but allow him the freedom of choosing research targets and methods. "This is where innovation and discovery is fostered,” says Borden. "It's where research is in control.”

Gries is currently working on many research projects with a variety of companies. But he distills all of his research down into one notion about insects: "It's just learning their languages, and how to talk back,” he says.

Desiree Willis is a senior majoring in neurobiology and technical communication at the University of Washington.

Image

Top: SFU biologist and IRC recipient Gerhard Gries and his collaborators (left to right): Grigori Khaskin, Stephen Takacs, and Regine Gries. The researchers are standing by to watch bed bugs come out of hiding. The insects are stimulated by carbon dioxide in the breath of their four keen observers. Photo: Carol Thorbes/SFU