Eriocraniella aurosparsella

Distinguished from other Eriocraniidae by the combination of immaculate forewings lacking pattern elements, bronzy to purplish iridescence, and the specific coastal California distribution. The uniform scaling of the hindwings is also a useful character. Larval mines are distinctive: initially linear and following the leaf margin, then abruptly enlarging into a large full-depth blotch on Quercus kelloggii.

Adults are small moths with wingspan 8–9 mm in males and 7.5–8.5 mm in females. Forewings are immaculate brownish fuscous, usually with distinct bronzy to light purplish iridescence. Hindwings are similar but less lustrous, uniformly covered with relatively broad scales.

Coastal and near-coastal habitats supporting California black oak (Quercus kelloggii), including oak woodlands and mixed evergreen forests in the Coast Ranges.

Western United States: southern Oregon south through the California Coast Ranges to Santa Clara County and Santa Cruz Island.

Adults on wing from late February to late May. One generation per year.

Larvae feed exclusively on Quercus kelloggii (California black oak), mining leaves.

• Quercus kelloggii - obligate larval hostCalifornia black oak; larvae mine leaves

Larvae mine leaves of Quercus kelloggii. The mine begins as an elongate linear track following the leaf margin, then abruptly enlarges to form a large, full-depth blotch. Larvae have dark brown body and uniformly dark brown head. Pupation presumably occurs in soil or leaf litter, though not explicitly documented. Adults emerge in late winter to spring.

Leaf miner on California black oak; specific ecological impacts unknown.

• Other Eriocraniella speciesMay share general size and appearance; distinguished by distribution, host association, and wing pattern details where known.
• Other EriocraniidaeDistinguished by immaculate, iridescent forewings and specific mine morphology on Quercus kelloggii.

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• NCBI Taxonomy