Lymantriinae

Distinguished from other Erebidae subfamilies by the combination of densely hairy adults with non-feeding mouthparts, and larvae with characteristic tufted hair arrangements including urticating setae. The presence of tussock-like dorsal tufts in caterpillars separates them from superficially similar Arctiinae larvae. Female flightlessness and reduced wing development occurs in some genera (e.g., Orgyia, Lymantria) but is not universal.

Primarily associated with forest and woodland ecosystems. Larvae feed on diverse host plants including trees, shrubs, vines, herbs, grasses, and lichens. Many species exhibit broad host ranges relative to other Lepidoptera.

Cosmopolitan distribution spanning all continents except Antarctica. Highest diversity in sub-Saharan Africa, India, Southeast Asia, and South America. Notable absence from the Antilles and New Caledonia. Madagascar hosts approximately 258 species.

Mostly nocturnal; approximately 20 confirmed diurnal species and 20 additional likely diurnal species (based on reduced eye size) have been documented. Adult activity periods vary by species and latitude.

Adults do not feed. Larvae are herbivorous, feeding predominantly on trees and shrubs, with some species known from vines, herbs, grasses, and lichens. Many species are generalist feeders with broader host ranges than typical Lepidoptera.

• Populus - larval hostfor some species
• Salix - larval hostfor some species
• Milkweeds (Asclepias) - larval hostfor Euchaetes egle and related species; sequesters cardiac glycosides
• Douglas-fir - larval hostfor Orgyia pseudotsugata
• Various forest trees - larval hostbroad host range for many pest species

Complete metamorphosis: egg, larva, pupa, adult. Larvae incorporate urticating hairs into the cocoon. Emerging adult females of some species collect and store abdominal hairs to camouflage and protect egg masses. Eggs may alternatively be covered by hardening froth or camouflaged with collected debris. Some species exhibit gregarious larval behavior.

Larvae of many species possess detachable urticating hairs as a defense against predators. Some species exhibit acoustic aposematism: adults emit ultrasonic signals detectable by bats, advertising their chemical unpalatability. This has been documented in milkweed-feeding species that sequester cardiac glycosides.

Significant herbivores in forest ecosystems; many species function as defoliators. Larvae serve as prey for birds, bats, and parasitoid insects. Some species participate in Müllerian mimicry rings with other milkweed-feeding insects. Population outbreaks can substantially alter forest composition and structure.

Several species are major forestry pests causing economically significant defoliation, including Lymantria dispar (spongy moth), Lymantria monacha (nun moth), and Orgyia pseudotsugata (Douglas-fir tussock moth). Caterpillar urticating hairs cause dermatitis in humans and livestock. Some species have been subject to biological control efforts. Former family name Lymantriidae suppressed by ICZN ruling in favor of precedence.

• ArctiinaeSimilar hairy larvae, but Arctiinae caterpillars lack the distinctive alternating bristle and tussock hair arrangement; adults typically more brightly patterned
• HerminiinaeSister lineage within Erebidae; adults generally less hairy with different wing venation; larvae not tussock-forming

• moths
• tussock moths
• forest pests
• urticating hairs
• defoliators
• Erebidae
• chemical defense
• acoustic aposematism

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• To Be an Underwing Underfoot | Bug Squad
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