Hemihyalea edwardsii

Edwards' Glassywing

Family: Arctiidae · Class: Insecta · Order: Lepidoptera

Edwards' Glassywing (Hemihyalea edwardsii) is a moth species in the family Arctiidae, distinguished by its translucent wing patches that give rise to its common name. This relatively small moth has a wingspan typically ranging from 25 to 35 mm (1.0 to 1.4 inches). The forewings display a complex pattern of brown, gray, and cream coloration with distinctive clear or semi-transparent areas, particularly noticeable in the central portion of the wings. The hindwings are generally paler with similar translucent regions. Males can be distinguished from females by their more feathered antennae and slightly smaller size. Edwards' Glassywing is endemic to California, with records primarily from the coastal ranges and Sierra Nevada foothills. The species has been documented in several counties including Alameda, Contra Costa, Santa Clara, and San Mateo, though its full distribution within the state remains incompletely mapped. Historical records suggest the species may have had a broader range, but current populations appear to be localized and scattered. The moth inhabits oak woodlands and mixed chaparral communities, typically at elevations between 150 and 1,200 meters (500 to 4,000 feet). Adults are most commonly found in areas dominated by coast live oak (Quercus agrifolia) and interior live oak (Quercus wislizeni), which serve as primary host plants for the larvae. The species shows preference for oak-dominated slopes and canyon bottoms where moisture levels remain relatively stable throughout the dry season. Adults are active primarily during spring and early summer months, with peak flight periods occurring from April through June. The species is nocturnal, with adults attracted to artificial lights during nighttime hours. Females lay eggs singly on oak leaves, typically on the undersurface of younger foliage. Larvae feed on oak leaves, developing through several instars before pupating in soil litter beneath host trees. The species appears to have a single generation per year, overwintering in the pupal stage. Like many California endemic lepidopterans, Edwards' Glassywing faces conservation challenges related to habitat loss and fragmentation. Urban development and conversion of oak woodlands have reduced available habitat throughout much of the species' range. Climate change poses additional threats through altered precipitation patterns that could affect oak forest health and the timing of larval development. The species' dependence on mature oak ecosystems makes it particularly vulnerable to habitat degradation. Fire management practices that eliminate understory vegetation where pupae overwinter may also impact local populations. While not currently listed under state or federal endangered species legislation, the moth's limited distribution and specific habitat requirements suggest it may warrant monitoring to assess population trends and habitat condition.

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