UV Light Best for Luring Cigarette and Drugstore Beetles
By Edward Ricciuti
Their common names—cigarette beetle and drugstore beetle—only hint at the amazingly eclectic and destructive diet of two related insects, which can wreak havoc on products stored in home pantries, warehouses, businesses, and even museums and libraries. New research by scientists at Hamamatsu University and Okayama University in Japan documents that LED ultraviolet (UV) traps can be used to monitor populations of these insects, an important step in controlling them. The study is published in the Journal of Economic Entomology.
While its name is something of an anachronism, now that smoking has lost its allure, the cigarette beetle (Lasioderma serricorne) is notoriously fond of eating stored tobacco. That’s just for starters. Also on its menu are a host of other products, ranging from dried fish to cereals, even leather and upholstery, and pyrethrum that can kill a cockroach. Meanwhile, the drugstore beetle (Stegobium paniceum)—a saying claims it “eats everything but cast iron”—goes it one better. As its name implies, its diet includes medicinal herbs and other pharmaceutical products, including strychnine. Both beetles, which are only a couple of millimeters long, prey on museum specimens and books, as well.
As the old adage about moths drawn to a flame indicates, many insects demonstrate phototaxis, movement towards light. Not just that, but various insects seem to prefer different wavelengths of light. A previous study in a laboratory setting indicated that the cigarette beetles are attracted more to ultraviolet and blue light wave ranges than others. However, blue light and UV light used in the study were not of equal intensity. Nor did researchers test wild beetles on their home turf, in a place where they naturally live and feed.
The new study, on the drugstore beetle as well as the cigarette beetle, was done in the laboratory and with an LED light trap in a building storing soy flour. In the laboratory study, the intensity of both types of light was equalized by adjusting the rate at which light particles, or photons, were emitted. When of equal intensity, UV light attracted both beetles much more powerfully than blue light. Another first for the study was showing that the drugstore beetle is attracted to UV light as well and responds to it in pretty much the same fashion as its relative.
In the laboratory study, beetles were allowed to walk or fly in a small arena equipped with a light source. The field study was carried out inside a storehouse in Kurashiki City, Okayama Prefecture, Japan, where wild populations of cigarette and drugstore beetles coexist.
The researchers opine that the addition of chemical lures to light traps make for a potent weapon against both beetles.
“Previously, we suggested light traps in combination with pheromone lures, i.e., multi-factor approach, may provide good solution to control L. serricorne,” they write. “Therefore, examination of the attractiveness of LED light traps with chemical lures is required to control S. paniceum as well as L. serricorne in the future.”
Journal of Economic Entomology
Ed Ricciuti is a journalist, author, and naturalist who has been writing for more than a half century. His latest book is called Bears in the Backyard: Big Animals, Sprawling Suburbs, and the New Urban Jungle (Countryman Press, June 2014). His assignments have taken him around the world. He specializes in nature, science, conservation issues, and law enforcement. A former curator at the New York Zoological Society, and now at the Wildlife Conservation Society, he may be the only man ever bitten by a coatimundi on Manhattan’s 57th Street.