Moths of North Carolina
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View PDFTischeriidae Members: 3 NC Records

Coptotriche fuscomarginella (Chambers, 1875) - No Common Name



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Taxonomy
Superfamily: Tischerioidea Family: TischeriidaeP3 Number: 230024.00 MONA Number: 139.00
Comments: Coptotriche is a genus of specialized leafminers that currently consists of 28 recognized Nearctic species. Most species fall within one of two major groups. Members of the first group typically have orangish to yellowish forewings (rarely white) and specialize on oaks and chestnuts, while members of the second group have dark gray, brown, or blackish forewings and mostly feed on members of the Rosaceae (Braun, 1972; Eiseman, 2019).
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONATechnical Description, Adults: Braun (1972)Technical Description, Immature Stages: Braun (1972); Eiseman (2019).                                                                                 
Adult Markings: The following is from Braun's (1972) description based on studies of 15 specimens from throughout the range of the species. The face, the forward projecting scales of the tuft, and the antennal scape are all white, while the crown varies from whitish to ocherous. The forewing is typically reddish ocherous, but sometimes paler, while the costal margin, the apical fourth of the wing, and the outer half of the dorsal margin are reddish fuscous. The scales in the apical fourth are dark-tipped. Dark specimens have a purplish tinge in the outer half of the costal margin where the line of dark scales widens. The cilia are typically reddish ocherous, but are more reddish fuscous in dark specimens. They become paler toward the tornus only in pale specimens. The hindwing is very narrow, pale ocherous, and usually has a reddish tinge. The cilia are reddish ocherous. The legs are pale ocherous, and the posterior tarsi are shaded with fuscous. The abdomen is pale ocherous, with fuscous dusting beneath and sometimes above.
Wingspan: 6.5-7.0 mm (Braun, 1972).
Adult Structural Features: Braun (1972) provides keys for identifying males and females based on genitalia. Her verbatim descriptions of the genitalia are as follows: vinculum not produced, nearly right-angled; apex of costa of harpe acute, setae long; anellus rounded conical, minutely spined; forks of aedeagus very narrow; forks of uncus widely separated, acuminate. Dorsal margin of segment 8 fringed with very long setae. Female genitalia: ovipositor lobes much larger than the very small lateral lobes, densely clothed with small peg setae; sex opening circular, with lateral sclerotized projections, enlarged portion of ductus bursae not spined, constriction beyond minutely spined, bursa copulatrix minutely tuberculate; posterior apophyses gradually widening to tip; segment 8 not reduced, broad posteriorly, arms of patibulum diverging from segment 8 near the median line, articulating in a swollen area of the anterior apophyses; prela small, short.
Immatures and Development: As a larva mines a leaf, it produces a gradually widening, full-depth tract that is translucent and trumpet-shaped. The frass is retained in the mine and packed in a gradually widening track back toward the beginning of the mine, with only a few scattered particles in the outer area of the mine. A thin silken tube leads from the feeding area to the packed frass track. Pupation usually occurs over a lateral vein in an elongate chamber, with the upper epidermis drawn into many fine folds (Braun, 1972). Eiseman (2019) observed that the pupation chamber is typically torn at each end as Braun described for C. zelleriella.
Distribution in North Carolina
Distribution: Coptotriche fuscomarginella is spottily distributed in the eastern US where it has been documented in Ohio, Kentucky, New York, Massachusetts, New Jersey, Virginia, and the Carolinas (Braun, 1972; Eiseman, 2019). Eiseman (2019) reared specimens from North and South Carolina (localities not reported), and Tracy Feldman reared an adult from a mine collected from Scotland Co.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Immature Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: Based on scattered records from the eastern US, the adults appear to be active from late spring through August.
Habitats and Life History
Habitats: This species is dependent on chestnuts and oaks for reproduction and is presumably restricted to forests or successional habitats with oaks or chestnuts.
Larval Host Plants: The larvae mine the leaves of chestnuts and oaks. Braun (1972) reared Kentucky specimens from American Chestnut (Castanea dentata), Chestnut Oak (Quercus montana) and Chinquapin Oak (Q. muehlenbergii). Eiseman (2019) also listed Bear Oak (Q. ilicifolia), Willow Oak (Q. phellos), and Black Oak (Q. velutina) as hosts. As of 2021, we have two records that are both from Blackjack Oak (Q. marilandica) in the Sandhills.
Observation Methods: Coptotriche fuscomarginella appears to be uncommon in North Carolina. Direct searches for the mines beginning in late spring or early summer may be the best way to document local populations. This should be coupled with the rearing of adults. Mine characteristics -- in combination with the presence of dark-tipped scales on the apical fourth of the forewings -- should be sufficient to distinguish this species from other species that mine oaks such as C. zelleriella. Most records from the eastern US are from reared adults, suggesting that this species is not strongly attracted to lights.
Wikipedia
See also Habitat Account for General Oak-Hickory Forests
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: [GNR] SU
State Protection:
Comments:

 Photo Gallery for Coptotriche fuscomarginella - No common name

Photos: 5

Recorded by: Jim Petranka and Bo Sullivan on 2021-08-31
Moore Co.
Comment: An adult that was reared from a mine on Blackjack Oak (see companion photos of the mine from 2021-08-09).
Recorded by: Jim Petranka and Bo Sullivan on 2021-08-09
Moore Co.
Comment: Occupied mine was on Quercus marilandica.
Recorded by: Jim Petranka and Bo Sullivan on 2021-08-09
Moore Co.
Comment: Occupied mine was on Quercus marilandica.
Recorded by: Jim Petranka on 2021-08-09
Richmond Co.
Comment: Unoccupied mine was on Quercus marilandica.
Recorded by: Jim Petranka on 2021-08-09
Richmond Co.
Comment: Unoccupied mine was on Quercus marilandica.