Inchworms

Inchworms are the larval stage of geometer moths, belonging to the family Geometridae. They are often called measuring worms or spanworms because of their distinctive looping gait, which appears to measure the distance they travel as they move.

Physically, inchworms have a slender body and typically lack several pairs of prolegs that are common in other caterpillars. Most species retain only two or three pairs of prolegs near the rear, which causes them to move by extending forward and then pulling the hind end forward in a characteristic loop. Their appearance often mimics twigs or other plant parts, providing camouflage from predators.

Ecologically, inchworms are mostly herbivorous, feeding on a wide range of plant leaves. They occur in many habitats, including forests, gardens, and agricultural areas. Some species can become pests, defoliating trees, shrubs, or crops and causing economic damage in orchards and plantations.

Life cycle and behavior follow a typical moth larva pattern. Eggs are laid on suitable host plants and hatch into larvae, which undergo several molts before pupating. Pupation may occur in the soil, leaf litter, or within a silken cocoon, depending on the species. Adults are moths that are generally nocturnal, with wings held flat or tent-like when at rest.

Distribution is global, with species adapted to a broad range of climates. Inchworms play roles in food webs as herbivores and as prey for predators, and they can serve as indicators of environmental health in some ecosystems.