Beetle may drive up coffee prices.

An incestuous insect that is proving to be resistant to pesticides may drive up the price of coffee, scientists predict. A new strain of the coffee berry borer, a beetle that is the most common pest of coffee plants worldwide, "may represent a serious threat to the international coffee industry" because it is resistant to the most commonly used coffee insecticide, endosulfan.

Luc Brun of the Institut Francais in New Caledonia first identified the resistance in this beetle in his country in 1989. At that time, New Caledonia, located in the South Pacific midway between Australia and the Fiji Islands, had many coffee farmers. Now, however, coffee farmers in that country are switching to other crops--in part because of lower worldwide coffee prices, and in part because of the pest.

As their name suggests, the coffee berry borers (Hypothenemus hempei) drill holes in the coffee berries and lay eggs inside the beans. Of the beetles that hatch, females outnumber males by a 10-to-1 ratio. The few males in the brood are unable to fly and never leave the coffee bean. These male beetles mate with their siblings before the mobile females flee the bean. "This incestuous relationship increases the likelihood that offspring will receive two doses of the resistance gene. Because of this, the resistance is likely to spread throughout the population much faster," explains Jeff Stuart, assistant professor of entomology, Purdue University.

The coffee berry borer is intriguing to scientists because recent discoveries indicate that the beetle may be an intermediate step in the evolution of one of nature's genetic mysteries...