Of the five species of North Americanbumble bees, two are facing steep population declines and one may be extinct. These bigger, gentler cousins of the imported honey-bee play a crucial role in pollinating flowering plants and their disappearance could prove disastrous to ecosystems. It could also provoke an economic disaster: New research shows that bumble bees and other insects provide $57 billion in pollination services as well as other free labor in the U.S. alone.

"Most insects tirelessly perform functions that improve our environment and lives in ways that scientists are only beginning to understand," explains entomologist John Losey of Cornell University. "Don't let the insects' small stature fool you, these minute marvels provide valuable services."

Losey and his colleague Mace Vaughan of the Xerces Society for Invertebrate Conservation undertook the task of estimating the monetary value of insect activity in the U.S. Confining themselves to four activities that could be rigorously calculated--processing cattle dung, controlling pests, pollinating plants and serving as food for wildlife--the scientists derived conservative figures for the value of these services.

For example, without insects as a food source, North American fisheries would collapse because most freshwater species subsist on flies and other insects. This means that the nearly $28-billion fishing industry relies on insects at its base. Dung beetles, too, contribute to the economy: without them, bovine dung festers on rangeland, increasing the number of pests and reducing the available forage for the cattle.

By deriving such economic estimates, the researchers hope to raise interest in insect conservation. They argue that preserving such ecosystem services should be an essential component of general land management. "Our biological infrastructure is vulnerable to degradation," Losey notes. "If we do not take care of it, it will break down and could seriously impact the economy."

Indeed, Vaughan observes that in the case of crop pollination, "the cracks in the infrastructure are already showing." A paper detailing these estimates appears in the April issue of BioScience.