The tortricids are a family of small to rather large moths with brown, rusty, gray, or tan coloration; some have bold or bright colors, but the majority are camouflaged to look like tree bark, dead leaves, or other unremarkable natural background. At rest, tortricids fold their wings rooflike over their bodies like a shallow roof. At rest, tortricids have a distinctive shape, resembling an arrowhead or a bell, with the forewing tips either squared-off or flared outward. The antennae are thin filaments, usually about half the length of the forewings. The labial palps (fingerlike structures next to the mouth) are either straight forward or tilted upward but not curved upward — this can look like a pointy nose or “snout.”
Wingspan: ½–1¼ inches.
Habitat and Conservation
Most occur in forested areas, fruit groves, or grasslands, spring through fall. Caterpillars feed on a wide variety of nonwoody plants, shrubs, and trees and either construct leaf shelters or bore into plants. Those that feed externally can propel droppings to a distant location to avoid giving away their presence.
Different tortricid species eat different kinds of plants. Some tortricid caterpillars may eat a wide variety of plant types, while others are limited to certain species, genera, or families of plants. The feeding behavior varies by species, too. Some tortricids are leaf rollers, using silk to make a leaf curl into a shelter they can hide in while they feed. Others burrow into plant tissues such as stems, causing the plant to form an enlarged chamber called a gall. Others bore into roots or fruits, while others eat seeds, flowers, or other plant parts.
Like other moths, tortricids begin as eggs, usually deposited on or near their food plants. After hatching, the caterpillars eat and grow, molting as they become larger. When fully grown, they pupate and emerge as an adult, winged moth. Some species may have multiple generations (broods) in a year; others might only have one.
Several species in this family are crop or orchard pests, and at least a few dozen of these are nonnative introductions, usually from Eurasia. A prime example is the codling moth (Cydia pomonella), whose larvae feed destructively on apple and pear fruits — they are the “worms” commonly seen tunneling in apples.
Some tortricid moths are employed as biological control species—these are introduced into a continent or region to help control some other species (usually an invasive exotic plant) that is out of control. An example is Episimus utilis, a native Brazilian tortricid that is used to help control the invasive Brazilian peppertree or “Christmas berry,” which is invasive in Florida and Hawaii. Its caterpillars eat the developing seeds inside the pods. Similarly, two species of tortricids show promise for combating the thorny, globally invasive yellow Himalayan raspberry. A key in each case is to determine how specialized the possible control species is in its food habits.
In addition to tortricids used purposefully to control nonnative invasive plants, many tortricids help control native weed species that are problematic for agricultural or landscaping interests.
Some tortricid species are serious forest pests. The eastern spruce budworm (Choristoneura fumiferana), every thirty years or so, has a huge population explosion. When this happens, their caterpillars can devastate large swaths of conifer forests; this is especially problematic in Canada and in northern US states, where spruce and fir trees dominate the wooded areas. The Cape May, Tennessee, and bay-breasted warblers love to eat spruce budworms, and their populations expand in years when spruce budworms have big outbreaks.
The leafrolling, gall-living, and burrowing habits of the larvae, and the camouflage coloration of adults, are indications that most of these moths are prey items sought after by birds and other animals. Doubtless many more tortricids become a meal for predators than survive to create offspring of their own.