It's not just birds that control insects in tropical forests and farmland. Bats may be doing at least as much of the work, according to two new field studies.

The abundance of caterpillars, beetles and other arthropods in tropical ecosystems offers fine dining for predators. Ecologists as well as farmers want to monitor bird and bat diets, which affect the rest of the food web and determine how much the insects damage plants.

Previously, researchers measured the dining power of birds by draping plants with bird-proof netting and then monitoring insect populations of the danger-free zone inside. But the netting was left on day and night, keeping out insect-hunting bats ...