Rhyacia quadrangula

The species can be distinguished by its specific wing measurements (36–38 mm wingspan) and geographic distribution pattern. Definitive identification likely requires examination of genitalic structures or molecular analysis, as is typical for many noctuid species with similar external morphology.

Adults have a wingspan of 36–38 mm. Specific details of wing pattern and coloration are not documented in available sources.

Specific habitat associations are not documented. Based on its distribution, the species likely occupies open tundra, boreal forest edges, and subarctic grassland habitats.

Disjunct transarctic and boreal distribution: Iceland, Greenland, central Asia (including Pamir Mountains), northern Canada (Quebec, Northwest Territories, Manitoba, Nova Scotia, Newfoundland and Labrador), and northwestern United States.

Adults are on wing from July to September, with peak activity during late summer.

Larvae feed on Gramineae species (grasses). Adult feeding habits are not documented.

• Gramineae - larval food plantgrass family

Complete metamorphosis with documented larval and adult stages. Specific details of egg, pupal, and overwintering stages are not available.

As a grass-feeding noctuid, larvae likely function as primary consumers in tundra and boreal grassland ecosystems. Adults may serve as prey for nocturnal insectivores including bats and birds.

• Other Rhyacia speciesSimilar external morphology; differentiation requires detailed examination of genitalia or geographic context
• Noctuinae with 36–38 mm wingspanSize overlap with many boreal noctuids; identification requires additional diagnostic characters

• noctuid moth
• transarctic distribution
• grass feeder
• boreal
• tundra

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Hughes Mountain redux | Beetles In The Bush
• Botanizing at Castlewood State Park | Beetles In The Bush
• Dispelling Urban Myths With Science Can Save Your Ash