From butterflies to grasshoppers, many delicate little things that run our world are in dire trouble. Not just in regions where human activity directly affects the landscape, but even in remote, human-free zones, a new study finds.

The loss of insects in key areas around the globe has been attributed in the past to the deliberate reduction of biodiverse habitats and changes in local climate. Now it's clear these forces stretch far beyond our immediate spheres of influence.

In areas relatively undisturbed by direct human activity, University of North Carolina biologist Keith Sockman recorded a dramatic drop of over 70 percent of flying insects in just 20 years.