Moths of North Carolina
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View PDFGracillariidae Members:
Parectopa Members:
77 NC Records

Parectopa robiniella Clemens, 1863 - Locust Digitate Leafminer Moth



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Taxonomy
Superfamily: Gracillarioidea Family: GracillariidaeSubfamily: GracillariinaeTribe: [Gracillariini]P3 Number: 330181.00 MONA Number: 657.00
Comments: The genus Parectopa contains around 40 species that are found worldwide, including nine species in North America. All are very small moths that are specialized leafminers.
Species Status: Parectopa robiniella is native to the eastern US and adjoining areas of southern Canada, but its range has expanded in North America with the planting and spread of its primary host (Black Locust; Robinia pseudoacacia) outside of its natural range. Parectopa robiniella became established in northern Italy around 1970 and subsequently spread to many regions of Europe. In Europe it feeds entirely on Black Locust, which is widely planted as an ornamental, and as a source of wood for heating, fencing, furniture and general construction (Hulujan et al., 2017). Due to a lack of natural control agents, P. robiniella can cause major defoliation of trees in Europe. In North America native parasitoids keep populations of P. robiniella in check and the host plants rarely suffer significant damage.
Identification
Field Guide Descriptions: Beadle and Leckie (2012); Leckie and Beadle (2018).Online Photographs: MPG, BugGuide, GBIF, BOLDTechnical Description, Adults: (Eiseman 2019)Technical Description, Immature Stages: Weaver and Dorsey (1967); Eiseman (2019).                                                                                 
Adult Markings: Adults have a dark brown head that is topped with elongated, white scale tufts. The forewings are dark brown with three oblique silvery costal streaks that alternate with three dorsal oval blotches or streaks. Near the tip of the wing, a transverse, curved silvery line passes from the costa to the tornus. There are also two converging dark brown to black lines at the base of the cilia that do not meet (Eiseman 2019). P. lespedezaefoliella is similar, but the curved silvery line is either absent or greatly reduced, and the two dark lines at the base of the cilia touch (or nearly touch) one another. This species is most easily documented by searching for the distinctive digitate blotch mines on Black Locust (Robinia pseudoacacia) or other legumes that serve as host plants.
Wingspan: 7-8 mm.
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: Females deposit eggs on the lower leaf surfaces, typically basally near the midrib or a larger vein. A hatchling initially makes a linear underside mine, then expands this to form a triangular, whitish blister. As the larva develops, it switches to mining the upper surface and eventually expands the mine to produce a distinctive digitate blotch mine that is normally centered on the midrib. The mine is initially pale green, but turns yellowish brown with age. Frass is either deposited in the lower surface mine or outside of the upper mine, so that the digitate blotch mine appears clean (Eiseman 2019). The late instar larvae are light green and pupation occurs in a flat, white cocoon that is spun outside of the mine.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Parectopa robiniella is native to eastern North America. Populations occur in southern Canada (Ontario; Quebec; Nova Scotia) and throughout much of the eastern US to as far south as Florida and the Gulf Coast. In North Carolina, P. robiniella occurs throughout much of the lower to upper-elevations of the Blue Ridge, as well as in the Piedmont and western Coastal Plain. Populations are restricted to sites where Black Locust or other host plants occurs locally. Records from iNaturalist include Stokes and Scotland counties.
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
Habitats and Life History
Habitats: This species is often found in open woodlands and along roadways with Black Locust and other legumes that are host species.
Larval Host Plants: Black Locust (Robinia pseudoacacia) appears to be the primary host plant, but the digitate leaf mines can be found on other legumes, including species of Amorpha, Desmodium, Galactia, and Lespedeza (Eiseman 2019). We also have records of it using American Groundnut (Apios americana), Bristly Locust (R. hispida) and Dwarf Locust (R. nana). - View
Observation Methods: This species can be easily detected by searching for the conspicuous leaf mines on Black Locust and other host plants.
Wikipedia
See also Habitat Account for Locust Groves and Thickets
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR S4
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: Populations are common in the Blue Ridge and western Piedmont, but more spotty further east. Overall, the species appears to be secure in the mountains; the status elsewhere is less certain.

 Photo Gallery for Parectopa robiniella - Locust Digitate Leafminer Moth

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

Recorded by: R. Newman on 2023-09-28
Carteret Co.
Comment: Mine was on Galactia volubilis.
Recorded by: David George, Stephen Dunn, Jeff Niznik on 2023-07-31
Macon Co.
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Recorded by: Jim Petranka and Bo Sullivan on 2023-05-17
Richmond Co.
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Recorded by: David George, Bo Sullivan on 2023-05-02
Carteret Co.
Comment: mines abundant on Black Locust
Recorded by: David George, Bo Sullivan on 2023-05-02
Carteret Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-10-21
Rutherford Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-10-06
Burke Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-09-13
Rutherford Co.
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Recorded by: Jim Petranka on 2022-08-28
Richmond Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-08-25
Clay Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-08-24
Macon Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-08-24
Macon Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-08-09
Watauga Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-08-02
Jackson Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-08-02
Jackson Co.
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Recorded by: Jim Petranka on 2022-06-09
Madison Co.
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Recorded by: tom ward on 2022-05-30
Buncombe Co.
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Recorded by: Jim Petranka and Becky Elkin on 2022-05-26
Wilson Co.
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Recorded by: Jim Petranka on 2022-05-21
Madison Co.
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Recorded by: Jim Petranka on 2022-05-21
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-10-20
Surry Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-10-19
Wilkes Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-10-14
Yancey Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-10-11
Burke Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-09-24
Henderson Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-09-12
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-09-10
Jackson Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-09-10
Transylvania Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-09-10
Transylvania Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-09-10
Transylvania Co.
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