A love affair with bugs

June 05, 2006, volume 36, no. 3
By Carol Thorbes

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A bug lover since childhood, Simon Fraser University graduand Melanie Hart is known as an eccentric among her lab mates because of her expanding insect zoo, perched above her workbench.

The zoo has become a refuge for more than 100 multi-legged creatures, no longer of any use to her colleagues.

“I've been in love with bugs since the age of five, when I got one of my most memorable birthday gifts, a bug catcher. By the time I was eight, I was stashing ants in my school desk,” says Hart, as she struggles to retrieve one of three, seven-centimetre giant cave cockroaches crawling up her arm.

This budding entomologist's attraction to insects is raising as many academic eyebrows as it is amusing her peers. She has just completed her master's in biology.

Under the supervision of Gerhard Gries, internationally renowned for his understanding of chemical and bioacoustic communication between insects, Hart has been researching what prompts peach twig borers to have sex.

The tiny destructive moths, only two centimetres in length, disfigure orchards, devaluing almonds and making fruits vulnerable to juice sucking wasps.

Two years of trial-and-error experiments at Ambercott Acres, an organic fruit orchard in the British Columbia Interior, have led Hart to discover sound communication in the gelechiid moth family.

For these barely visible pests, getting together to copulate requires more than the male using his sense of smell, like most moths, to pick up female sex pheromones (message-bearing chemical compounds). Twig borers engage in an elaborate courtship involving the emission of sex pheromones and sounds that enable males and females to pinpoint each other's location in vast orchards.

Hart used dual audio and video recordings to observe female twig borers doing cartwheels before emitting sounds of love.

Bioacoustic communication among these moths was previously unknown. The discovery that their communication is audible to the human ear is creating a buzz among established researchers.

“Most moths communicate in the ultrasonic sound range, above the human hearing range. Only a few moths, such as the wax and clothes moths, are known to use sonic frequencies,” notes Hart, whose findings have resulted in an international Patent Treaty Cooperation patent application.

With Gries now as her doctoral supervisor, Hart is helping Phero Tech International develop a product that uses her research to disrupt peach twig borer mating sounds and control their orchard infestations.
Phero Tech, an SFU spinoff company in Delta, invents and distributes products using message-bearing insect chemicals to control pests.

Hart is now teasing out frequency signals in the moths' sex talk to find out exactly what their communication is driving them to do. “It's like being a linguist who is analyzing the function of words,” says Hart, a Latin lover, with a double major in English and  classics.

Hart, who loves teaching as much as she loves bugs,  won a faculty of science excellence in teaching award for 2005-2006.

She fits her teaching in between flying back and forth to Cawston, just outside of Keremeos, to spy on Ambercott Acres' moths.

As if she isn't busy enough buzzing back and forth between Vancouver and the Interior to monitor twig borers in flight, Hart has netted herself another project, overseas. This summer, she'll be helping the South Korean government assess whether a moth devastating that country's sweet potato crops uses sound to communicate and if itcan be controlled by blocking.

No doubt, Hart will be anxious to get back home to her multi-legged pets. It's unlikely she'll be able to get anyone to keep her giant African millipedes well groomed while she's away.

“My friends have grown accustomed to my eccentricity,” says Hart, as she lovingly uses tweezers to pluck parasites from a pet millipede's body segments, “but they don't like me bringing my pets home.”

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