"So you have a beetle, a mite, a tree, two kinds of fungi, and a bacterium," says Jon Clardy, Harvard Medical School professor of biological chemistry and molecular pharmacology who, along with Cameron Currie from the University of Madison-Wisconsin, is co-senior author on the study. "Discovering this particular bacterium, and the active molecule, has added the molecular dimension to this chemical ecology of this complex multi-lateral system. It highlights the importance of bacteria in ways that people don't really even think about."
The findings will be published in the October 3 issue of Science.
The ground work for this study began in 1999 when Currie published a paper demonstrating how leafcutter ants mediate their fungal environment through bacteria. Suspecting that this phenomenon may be common throughout the animal kingdom, Currie teamed up with Clardy to examine the pine beetle.
Pine beetles are like little landscape engineers, drilling through the bark and into pine trees, using fungus to create an environment in which to lay their eggs. As a result of this activity, thousands of miles of trees are destroyed each year, often resulting in widespread forest fires. Regions such as western Canada are particularly affected by this.
Experts have known that just like the fungus-growing ants, pine beetles also use fungus to feed their larvae, and that they often managed to avoid the adverse affects of pathogenic fungi often present in the tree. But the precise means by which they interact with fungal microbes has never been demonstrated.
Currie and research assistant Jarrod Scott discovered that the beetle carries a bacteria in a specialized compartm
|Contact: David Cameron|
Harvard Medical School