Macaria graphidaria

Distinguished from similar Macaria species by the bold, well-defined dark markings on the forewings, particularly the pronounced median band. Macaria signaria has more diffuse, less contrasting patterning. Macaria adonis typically shows more uniform gray coloration with fainter lines. Genitalia examination may be required for definitive identification of worn specimens.

Coniferous forests, particularly those dominated by Douglas-fir, ponderosa pine, and related Pinaceae. Occurs from low-elevation woodlands to montane forest zones. Associated with mature and second-growth stands.

Western North America, from British Columbia and Alberta south through the Rocky Mountains to Arizona and New Mexico. Also documented in coastal California and the Pacific Northwest.

Adults active primarily from May to August, with peak activity in June and July. Single-brooded in most of range; partial second generation possible in southern portions.

Larvae feed on foliage of conifers, particularly Pseudotsuga menziesii (Douglas-fir) and Pinus species (pines).

• Pseudotsuga menziesii - larval food plantprimary host
• Pinus - larval food plantsecondary host, various species

Complete metamorphosis with four stages: egg, larva, pupa, adult. Eggs laid on host foliage. Larvae feed externally on needles, developing through five instars. Pupation occurs in soil or leaf litter. Overwintering stage uncertain, likely as pupa or late-instar larva.

Adults nocturnal, attracted to light. Larvae solitary feeders, consuming needle tissue from conifer shoots. Not known to be gregarious.

Herbivore in conifer forest ecosystems. Larval feeding contributes to nutrient cycling and may influence needle turnover in dense populations. Serves as prey for forest-dwelling birds and arthropod predators.

Minor forestry pest; occasional localized defoliation reported but rarely economically significant. Attracted to artificial light sources in forested residential areas.

• Macaria signariaOverlapping range and similar size, but with less contrasting wing pattern and fainter transverse lines
• Macaria adonisSimilar habitat preference, but forewings more uniformly gray with reduced dark markings
• Macaria pustulariaComparable western distribution, distinguished by more mottled wing pattern with distinct reniform spot

• geometridae
• ennominae
• western north america
• conifer feeder
• forest moth

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life