Caterpillars have a significant effect on the numbers and types of plants in the rainforest. According to some scientists, they may eat more leaves than all other herbivores combined. Caterpillars are also the food source for many animals in the rainforest, ranging from birds to other insects. As a link in many different food chains, caterpillars play a complex role in conserving the biodiversity of the rainforest.

The first task of Earthwatch team members is to find the caterpillars. Munched upon leaves, a curled leaf, and of course, frass (term ecologists use for caterpillar droppings) are all signs of caterpillar activity. After samples of the host plant are collected, volunteers watch and record carefully how a caterpillar reacts to, or avoids potential predators like birds or rodents. Each caterpillar species has special adaptations to help it survive in its habitat.

Earthwatch team members then place the caterpillar in a plastic bag, hang it on a clothesline in a caterpillar "zoo," and examine it daily for signs of internal enemies. Wasps or flies might have laid eggs that are growing inside the caterpillar's body. If a caterpillar finally survives to adulthood, volunteers record the time period, and the kind of butterfly or moth that emerges.

So far, Dr. Dyer and Dr. Gentry have documented the behaviors and life histories of over 300 species of caterpillars. Many more species of caterpillar remain to be discovered. Their research brings practical benefits. One benefit is replacing harmful pesticides with the natural enemies of caterpillars to control caterpillar destruction of farmers' crops.

Photo courtesy of Dr. Grant Gentry/Earthwatch Institute