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Cockroaches' Own Sex Attractant Could Be Tool to Battle Infestations

Work of ESF's Dr. Fran Webster and colleagues

A chemist at the SUNY College of Environmental Science and Forestry (ESF) has identified the chemicals in a sex pheromone that female cockroaches use to attract males and has replicated the substance in his laboratory for the first time, possibly providing a new tool in the battle against a common urban pest.

The findings of ESF's Dr. Fran Webster and his colleagues are reported in this week's (Feb. 18) edition of the journal Science.

Scientists have tried for decades to break the chemical code, without success, until now.

The German cockroach, the subject of the study, is the most common cockroach pest. It is a major cause of allergies and asthmatic episodes, particularly among children, and spreads disease as it moves between human and animal waste and food products.

"It is the worldwide pest among cockroaches and it's very difficult to control," Webster said. "They are much more common in urban areas than rural ones. In an urban setting, anywhere you have filth, there's always a chance that there are cockroaches."

Like most insects, cockroaches communicate using chemical compounds called pheromones. Many of the pheromones can carry their message through the air much like a perfume, and sex pheromones are effective over long distances. In most cases, including the German cockroach, the female attracts males to her when she is ready to mate.

Webster's research has focused on breaking the code of these "long distance" messages used by insects.

The study in Science reports on the identification and laboratory synthesis of the specific chemicals found in the sex pheromone of the cockroach, which is known by the scientific name of Blattella germanica. The pheromone, called blattellaquinone, had been isolated previously by other scientists involved in the project, including Satoshi Nojima and Wendell L. Roelofs of Cornell University, and Coby Schal and Richard G. Santangelo of North Carolina State University.

The airborne pheromone could be used as a tool to survey and control cockroach populations, Webster said. It could be used as bait to determine the extent of an infestation, and then mixed with poison to eradicate the insects.

"It would prevent the need to spray poison widely," Webster said. "You could use it when and where it was needed most."

The work began at North Carolina State, where the pheromone was obtained from the insects, then moved to Cornell, where it was purified. Then it came to ESF, where Webster stabilized and identified it using a 600-megahertz nuclear magnetic resonance (NMR) spectrometer, the only one of its kind in Central New York. The NMR experiments allowed Webster to identify the chemicals in the compound and then replicate it in his laboratory. NMR technology allows a chemist to visualize a molecule by observing its constituent atoms, providing exquisitely detailed structural information about complex molecules, both natural and man-made.

The pheromone that Webster made in the laboratory was identical to the material produced by the cockroach.

The importance of the synthetic material, Webster said, is twofold: It allowed researchers to confirm the identification, and it lends itself to practical applications. Webster said a number of companies are interested in obtaining samples of the material to test in monitoring and control formulations. There is a patent pending on the pheromone and the companies might be interested in licensing the technology.

Webster is an expert in identifying tiny amounts of natural products. His textbook, "Spectrometric Identification of Organic Compounds," which was just released in its seventh edition in January, is used by Colleges and Universities worldwide. The sixth edition was translated into Spanish, Portuguese, Japanese, and Chinese.

In addition to identifying new pheromones, Webster is interested in reproducing pheromones in the laboratory and studying how they can be used to control insect pests. Pheromones are now being used to control agricultural, forestry, stored products, and urban insect pests using little or no pesticides. Pheromones are also widely used in integrated pest management programs.

Feb. 18, 2005

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