Acericecis

Presence of circular, eyespot-like galls with concentric rings of yellow and red on maple leaves is diagnostic. Each gall contains a single, sessile larva positioned at the center. Adults require microscopic examination for definitive identification; they resemble other small cecidomyiids but are associated exclusively with maple galls.

Deciduous forests and urban areas where maple trees (Acer spp.) grow, particularly red maple (Acer rubrum). Larvae develop within leaf tissue; pupae overwinter in soil beneath host trees.

Holarctic region, including North America and Europe. Documented from the United States (including Vermont), Denmark, and other temperate regions where maples occur.

Adults emerge in spring, typically April to May, when maple leaves are young and expanding. Larvae feed through late spring and early summer, then drop to the soil to pupate. Pupae remain in soil through summer, autumn, winter, and early spring before adult emergence.

Larvae feed on nutritive tissue induced within maple leaf galls. The feeding stimulates abnormal plant growth that provides specialized food tissue. Adults do not feed or feed only on nectar.

• Acer rubrum - obligatePrimary host; red maple leaves develop characteristic ocellate galls
• Acer - obligateGenus-level host specificity; all extant species induce galls on maple leaves

Holometabolous with one generation per year. Eggs are deposited on undersides of young maple leaves. Larvae hatch, attach with mouthparts, and secrete hormone-like compounds that induce gall formation. Larvae feed within galls for several weeks, then drop to soil and pupate. Pupae undergo diapause through winter, with adults emerging the following spring.

Females fly to tree canopies to oviposit on young leaves. Larvae are sedentary, remaining fixed at the gall center while manipulating host plant development through chemical secretions. The induced pigmentation patterns (carotenoid yellow and anthocyanin red rings) are not normal autumn colors but are actively produced by the larva's influence on leaf physiology.

As gall inducers, these midges create novel microhabitats on maple leaves. The galls may provide shelter for other arthropods, though specific inquiline relationships are not well documented. The larvae function as specialized herbivores that manipulate host plant metabolism.

Primarily of aesthetic and scientific interest. The eyespot galls are visually striking and may concern homeowners, but they cause minimal harm to established trees. Occasionally used as examples of plant-insect chemical interactions in entomology education.

• CecidomyiaOther gall midge genera in Cecidomyiidae; distinguished by host specificity (maples only for Acericecis) and the distinctive ocellate gall morphology with concentric pigmented rings
• AsphondyliaGall midge genus including holly berry midge; distinguished by host plant and gall type—Asphondylia induces berry or bud galls rather than leaf eyespot galls

• gall midge
• Cecidomyiidae
• maple
• Acer
• gall former
• Holarctic
• plant manipulation
• eyespot gall
• ocellaris

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• Maple Eyes – Ocellate maple gall midge, Acericecis ocellaris — Bug of the Week
• Archive — Bug of the Week