These creatures are known as Bagworm moth caterpillars, also called as larvae, belong to the Psychidae family. When they hatch, they create silk cocoons for themselves. These cocoons are strengthened with “cases,” which they build using leaves, twigs, and similar materials. These cases often look like tiny log cabins, earning them the name “case moths.” As they mature, they transform into adult bagworm moths. Sadly, during their larval stage, these caterpillars can harm plants and cause damage.
Bagworm moth caterpillars typically have a pale yellow color with black markings on their bodies. They usually grow to about 1.5 inches long and have six legs like most insects. After hatching, they quickly make silk cocoons.
Each bagworm larva weaves a silk cocoon and then constructs a protective “case.” These cases look different because they use materials from their surroundings. The most unique one looks like a tiny log cabin, but others might resemble a misshapen pinecone or a heap of leaves and twigs. The caterpillar keeps building up its case during its pupal stage. Cases can vary in size from less than 0.4 inches to 5.9 inches and have tapered ends at both openings.
Adult male bagworms are fuzzy and black with fully grown wings that span between 0.47 and 1.42 inches. Females, however, usually have tiny wings or none at all. They remain in a pupal state, partly inside their cocoon, throughout their lives.
Bagworm moths and their caterpillars are found worldwide on every continent except Antarctica. In the United States, they are spread across the eastern part and in states such as South Dakota, Nebraska, Kansas, and Texas. They live in areas where they can find plants to feed on, particularly in deciduous and coniferous forests. They may also wander into urban or suburban regions with similar trees or plant life. Sometimes, they become a problem by damaging vegetation in these areas.
Bagworm caterpillars mostly feed on the leaves and needles of trees and shrubs. They often target deciduous trees like maples, oaks, box elders, and willows, as well as coniferous trees such as pines, spruces, firs, junipers, and eastern red cedars. Occasionally, they may also go after fruit trees and flowers.
These caterpillars face threats from various birds like woodpeckers, sapsuckers, and sparrows, which prey on them. Additionally, a type of parasitic wasp called the ichneumon wasp lays its eggs inside the bagworms, using them as hosts for its young!
