Proteoteras aesculana Riley (Tortricidae: Olethreutinae: Eucosmini)
Common name: maple twig borer moth
FWL: 6.0–9.0 mm
Head, thorax variably colored, most often dark green, pale yellow-green, black, brown, or some combination of the four; forewing with ground color dark green with scattered black scales, patches of raised scales present; fasciae grayish-white, often suffused with dark green or navy blue scales; a crescent-shaped mark from mid-costa to the apex is present, but contrasts poorly with the adjacent fasciae; male forewing without costal fold, but the dorsal hindwing possesses a large subcostal hair-pencil surrounded by black scales; hindwing otherwise brown.
Male genitalia are characterized by a reduced uncus; lobe-like socii; valvae narrow, with well-developed cucullus; and sacculus bearing three to four large flattened setae towards distal end and patch of thin, dense setae towards base. Female genitalia are characterized by a long, narrow, and anteriorly enlarged lamella postvaginalis and corpus bursae with two signa.
The following account is summarized from MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338. and Powell (1962b)Powell (1962b):
Powell, J.A. 1962b. Biological and taxonomic notes on two California species of Proteoteras (Lepidoptera: Tortricidae). Pan-Pacific Entomologist 38: 191- 195..
Mature larva approximately 10 mm in length, robust; width of head 1.0–1.2 mm; head yellow-brown, with black pigmentation laterally; head darker in California specimens; thoracic shield yellow-brown with similar dark lateral pigmentation; legs brown; body pale grayish-white to yellow, pinacula slightly darker; anal shield yellow-brown; anal fork present, but poorly developed; SV group on A1, 2, 7, 8, 9 quite variable, but most often 3:3:2:1:1.
Detailed figures of larval chaetotaxy, including additional SV group combinations, is available in MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..
Proteoteras aesculana closely resembles several other species of Proteoteras but can be identified by the conspicuous black scaling around both sides of the costal hair-pencil on the dorsal surface of the male hindwing and differences in the shape and structure of the male valvae and female sterigma.
Proteoteras aesculana is broadly distributed in North America, from Nova Scotia to British Columbia, south to Florida, eastern Texas, and California. It appears to be absent from the Rocky Mountains and Great Basin.
The following account is summarized from Powell (1962c)Powell (1962c):
Powell, J. A. 1962c. Biological and taxonomic notes on two California species of Proteoteras (Lepidoptera: Tortricidae). Pan-Pacific Entomologist. 38: 191-195. and Solomon (1995)Solomon (1995):
Solomon, J. D. 1995. Guide to insect borers in North American broadleaf trees and shrubs. Forest Service Agriculture Handbook AH-706, USDA, Washington, D.C. 735 pp..
Adults have been collected from February to October but have a more restricted flight period in the northern portions of its range. Numbers of adults appear to peak in June and July, but there are likely multiple generations per year throughout most of its range. Oviposition has not been recorded, but likely takes place near the base of young buds and terminal shoots in the spring. Larvae bore into these buds and shoots and begin feeding downwards, eventually boring into twigs, producing a spindle-like gall. The total length of these feeding tunnels is approximately 40–46 mm. Pupation takes place outside of the tunnel after a total of five instars.
The preferred larval host appears to be maple (Acer spp.), especially boxelder (Acer negundo). Buckeye (Aesculus spp.) has also been recorded.
View full screen host table here
Authors: KA Austin, TM Gilligan, ME Epstein
Content last updated May 2025
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