Calycomyza eupatoriphaga

Adults are small flies, approximately 2–3 mm in length, with the reduced wing venation characteristic of Agromyzidae. Species-level identification requires examination of male genitalia and chaetotaxy; the original description provides diagnostic characters including specific arrangements of orbital setae and distinctive phallus structure. The leaf mines are more readily observed than adults: larvae produce irregular blotch mines with scattered frass, typically on the upper leaf surface of Eupatorium species. Mines begin as narrow, winding tracks that widen into blotches.

Associated with moist to wet habitats where host plants in the genus Eupatorium grow, including meadows, stream banks, pond margins, and woodland edges. Host plants include white snakeroot (Ageratina altissima, formerly Eupatorium rugosum) and other bonesets.

Eastern North America; documented from the northeastern United States and adjacent Canada. Records include New York, Pennsylvania, Massachusetts, and Ontario.

Adult emergence and larval mining activity occur during the growing season of host plants, primarily June through September in temperate regions.

Larvae feed as leaf miners within leaves of Asteraceae, specifically species in the tribe Eupatorieae including Eupatorium and Ageratina. Frass is deposited in scattered grains within the mine.

• Eupatorium - host plantprimary host genus; larval development occurs in leaves
• Ageratina altissima - host plantformerly Eupatorium rugosum; confirmed host in original description

Complete metamorphosis with egg, three larval instars, pupa, and adult. Eggs are laid on leaf surfaces. Larvae mine through mesophyll, feeding for approximately 1–2 weeks before pupating either within the mine or in soil. Pupation occurs in a brown, barrel-shaped puparium. Multiple generations per year likely in southern part of range.

Larvae are solitary leaf miners. When disturbed, larvae may attempt to escape by dropping from the leaf on a silk thread. Adults are weak fliers and remain close to host plant stands.

As a specialist herbivore, contributes to natural leaf damage and nutrient cycling in wetland and meadow ecosystems. The mines may provide entry points for secondary fungal pathogens. Parasitoid wasps in families such as Eulophidae and Braconidae have been reared from Agromyzidae mines and likely attack this species.

No direct economic importance. Occasionally observed by naturalists and leaf mine enthusiasts. The specific association with white snakeroot (Ageratina altissima) is notable because this plant contains tremetol, a toxin responsible for milk sickness in historical livestock outbreaks; the fly's ability to develop on this chemically defended host suggests physiological adaptation.

• Calycomyza artemisiaeAlso in genus Calycomyza and produces similar blotch mines on Asteraceae, but restricted to Artemisia hosts; mine frass pattern and adult genitalia differ
• Phytomyza eupatorivoraAnother agromyzid leaf miner on Eupatorium; produces linear mines rather than blotches and has different frass arrangement
• Liriomyza eupatoriiProduces serpentine mines on Eupatorium; distinguished by continuous frass line and different adult morphology

• leaf miner
• specialist herbivore
• Asteraceae
• wetland
• North America

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