Grammia edwardsi

Family: Erebidae · Class: Insecta · Order: Lepidoptera

Grammia edwardsi is a moth species belonging to the family Erebidae, subfamily Arctiinae, commonly known as tiger moths. This species was first described by Stretch in 1885 and is part of a diverse genus of moths found primarily in western North America. Like other members of the genus Grammia, G. edwardsi exhibits the characteristic robust body structure and broad wings typical of tiger moths. Adult Grammia edwardsi display the typical tiger moth morphology with forewings that are generally dark-colored, often featuring intricate patterns of lines, spots, or bands. The hindwings are typically brighter, frequently displaying warning coloration patterns in combinations of red, orange, yellow, or white with black markings. The wingspan of adults typically ranges from 35 to 55 millimeters (1.4 to 2.2 inches), consistent with other medium-sized Grammia species. The thorax is densely covered with scales, and the abdomen often shows banded patterns that serve as aposematic coloration. The historical and current distribution of Grammia edwardsi appears to be restricted to western North America, though specific range details require further documentation. Many Grammia species are associated with montane and high-elevation habitats, particularly in areas with suitable host plant communities. The species likely occurs in California, given its inclusion in state biodiversity databases, though precise county-level distribution data remains limited. Habitat preferences for G. edwardsi likely include areas supporting appropriate larval host plants. Tiger moth larvae, commonly called woolly bears, typically feed on a variety of herbaceous plants, shrubs, and sometimes trees. The specific host plant associations for this species require additional research, though many Grammia species utilize plants in families such as Asteraceae, Fabaceae, and Plantaginaceae. Adults are nocturnal and attracted to artificial lights, making them observable during nighttime surveys. The life cycle follows the typical lepidopteran pattern of complete metamorphosis. Eggs are laid on or near host plants, and larvae develop through several instars before pupating in soil or leaf litter. Adult flight periods vary by elevation and latitude but generally occur during warmer months. Larvae overwinter in most temperate Grammia species, emerging in spring to complete development. The conservation status of Grammia edwardsi remains poorly documented, with no apparent federal or state listing status as of December 2025. Like many specialized moths, the species may face threats from habitat loss, urbanization, light pollution, and climate change effects on host plant distributions and phenology. The lack of comprehensive survey data makes population trend assessment difficult. Many tiger moths, including Grammia species, serve important ecological roles as pollinators in adult form and as herbivores affecting plant community dynamics during larval stages. They also provide food resources for bats, spiders, and other predators. Further research is needed to document the specific ecological requirements, distribution, and conservation needs of G. edwardsi to ensure appropriate management of habitats supporting this species.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.