Moths of North Carolina
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View PDFGracillariidae Members: 72 NC Records

Acrocercops strigosa Braun, 1914 - No Common Name



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Taxonomy
Superfamily: Gracillarioidea Family: GracillariidaeSubfamily: GracillariinaeTribe: [Gracillariini]P3 Number: 330222.00 MONA Number: 697.00
Comments: The genus Acrocercops includes nine recognized species in North America. The adults of most species are rather boldly marked, and the larvae are leaf miners that produce linear blotch mines.
Species Status: Although this species appears to be uncommon throughout its range, observations made by Jim Petranka in Madison Co. indicate that local populations in NC can reach very high densities. The adults prefer dark resting spots during the day, and may enter homes through cracks or vents where their sheer numbers can become a nuisance. On 4 August, 2019, Jim Petranka estimated via direct count that there were 1,620 resting adults that were lining the walls and ceiling of a small wooden tool shed. Large aggregates of resting moths such as this have rarely been reported (e.g., Sourakov, 2018), and merit additional study.
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONATechnical Description, Adults: Braun (1914)Technical Description, Immature Stages: Braun (1914); Eiseman (2019).                                                                                 
Adult Markings: Acrocercops strigosa has pale brownish forewings with a series of seven oblique white lines that are roughly equidistant and parallel. The third line forks below the fold, and the fourth and fifth are slightly interrupted in the middle. There is a short white streak at the apex and a similar one beyond it that crosses the cilia. The legs are whitish gray with broad dark annulations (Braun 1914). Individuals characteristically rest with the front of the body raised well above the surface of the substrate.
Wingspan: 10 mm based on a male examined by Braun (1914).
Forewing Length: 4.3-5.1 mm (mean = 4.8 mm) for 10 NC specimens.
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae are leafminers on members of the white oak group. The early mine is a highly elongated, narrow, sinuous gallery. This later balloons into a very large, whitish blotch. The larva that is inside eventually consumes the entire parenchyma, which produces a distinctive blotch with tissue-paper thin walls. The mature larva eventually leaves the blotch and spins a dense, brownish cocoon in a fold of a leaf (Braun 1914; Eiseman 2019).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Acrocercops strigosa is found in eastern North America. Scattered populations occur in southern Canada (Ontario; Quebec) and in the US from Massachusetts and neighboring states westward to Ohio, and southward to KY, eastern Tennessee, and western NC. As of 2020, records for NC are mostly from lower-elevation sites in the Blue Ridge, along with one record from Stokes County (iNaturalist) in the Piedmont. White Oak is widespread in the eastern US, so factors other than host species availability likely determine this species southernmost and easternmost range limits.
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: Jim Petranka studied a population in Madison Co., North Carolina and observed the adults almost year-round. In this population the adults overwinter and occasionally appear at lights on warm fall and winter nights. The primary breeding bout occurs in late March through early May after the leaves of oaks are fully expanded. At this time large numbers of mines are often present on White Oak leaves. Data from observations of adults at UV-lights suggest that there may be one or two additional smaller broods -- one in late June through August -- and a second from September-October. However, occupied leaf mines have not been observed during these time periods to confirm breeding. Jim Petranka observed a thousand or more adults on multiple occasions in a small tool shed in August through early September that appeared to be aestivating. They became active by mid-September and dispersed into the surrounding forest shortly thereafter. The adult began reappearing in large numbers the following year in mid-July.
Habitats and Life History
Habitats: Little information is available on habitat preferences. Specimens from Madison Co. occur at a low-elevation, mixed conifer-hardwood forest with White Oak. White Oak and Rock Chestnut Oak are primary hosts for the larvae, and local populations are presumably restricted to sites that have one or both of these species. The occurrence of large numbers of adults in a darkened tool shed in Madison County suggests that large hollow trees may provide important microhabitats for these small moths.
Larval Host Plants: The larvae feed on members of the white oak group and have been observed using both White Oak (Quercus alba) and Rock Chestnut Oak (Q. montana) in North Carolina.
Observation Methods: The leaf mines can be located by searching the foliage of White Oaks or Chestnut Oaks after the leaves are fully formed in the spring. The foliage of oak seedlings or small saplings often have numerous mines. The adults are attracted to both black lights and incandescent lights, but general prefer areas with dim lighting such as window panes or areas that are several feet from a bright light.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR [S4S5]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species appears to be locally common in some areas of the lower mountains.

 Photo Gallery for Acrocercops strigosa - No common name

40 photos are available. Only the most recent 30 are shown.

Recorded by: Jim Petranka and Becky Elkin on 2021-09-12
Madison Co.
Comment: Unoccupied mines were common on Chestnut Oak (Q. montana)
Recorded by: Jim Petranka and Becky Elkin on 2021-08-26
Yancey Co.
Comment: Unoccupied mines were common on White Oak.
Recorded by: Jim Petranka, Becky Elkin and Bo Sullivan on 2021-08-02
Ashe Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-07-23
Graham Co.
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Recorded by: Jim Petranka on 2021-07-16
Madison Co.
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Recorded by: Jim Petranka on 2021-07-14
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-07-13
McDowell Co.
Comment: Unoccupied mines were on White Oak.
Recorded by: Jim Petranka and Becky Elkin on 2021-06-30
Mitchell Co.
Comment: Unoccupied mines were on Quercus montana.
Recorded by: Jim Petranka and Becky Elkin on 2021-06-27
Buncombe Co.
Comment: Unoccupied mines were common on Chestnut Oak (Q. montana)
Recorded by: Jim Petranka on 2021-06-21
Buncombe Co.
Comment: Unoccupied mines were common on Chestnut Oak (Q. montana)
Recorded by: Jim Petranka on 2021-04-26
Madison Co.
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Recorded by: Jim Petranka on 2021-04-20
Madison Co.
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Recorded by: Jim Petranka on 2021-04-14
Madison Co.
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Recorded by: Jim Petranka on 2021-03-12
Madison Co.
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Recorded by: Jim Petranka on 2020-11-10
Madison Co.
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Recorded by: Jim Petranka on 2020-10-12
Madison Co.
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Recorded by: Vin Stanton on 2020-09-14
Buncombe Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-07-20
Jackson Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-07-14
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-07-11
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-05-23
Madison Co.
Comment: One of several active mines that were on White Oak and Burr Oak as seen here. Note the puffy nature of the blotch portion of the mine.
Recorded by: Jim Petranka and Becky Elkin on 2020-05-16
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-04-06
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-03-10
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2019-12-29
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2019-10-28
Madison Co.
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Recorded by: Jim Petranka on 2019-10-15
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2019-10-03
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2019-09-17
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2019-08-04
Madison Co.
Comment: A close-up of adults resting during the day in a small wooden shed. Based on an estimate from a complete count using groups of 10 moths, there were 1,620 adults in the shed.