Where have all the insects gone?

Entomologists call it the windshield phenomenon. "If you talk to people, they have a gut feeling. They remember how insects used to smash on your windscreen," says Wolfgang Wägele, director of the Leibniz Institute for Animal Biodiversity in Bonn, Germany. Today, drivers spend less time scraping and scrubbing. "I'm a very data-driven person," says Scott Black, executive director of the Xerces Society for Invertebrate Conservation in Portland, Oregon. "But it is a visceral reaction when you realize you don't see that mess anymore."

Some people argue that cars today are more aerodynamic and therefore less deadly to insects. But Black says his pride and joy as a teenager in Nebraska was his 1969 Ford Mustang Mach 1—with some pretty sleek lines. "I used to have to wash my car all the time. It was always covered with insects." Lately, Martin Sorg, an entomologist here, has seen the opposite: "I drive a Land Rover, with the aerodynamics of a refrigerator, and these days it stays clean."

Though observations about splattered bugs aren't scientific, few reliable data exist on the fate of important insect species. Scientists have tracked alarming declines in domesticated honey bees, monarch butterflies, and lightning bugs. But few have paid attention to the moths, hover flies, beetles, and countless other insects that buzz and flitter through the warm months. "We have a pretty good track record of ignoring most noncharismatic species," which most insects are, says Joe Nocera, an ecologist at the University of New Brunswick in Canada.