Moths of North Carolina
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14 NC Records

Olethreutes nigranum (Heinrich, 1923) - Variable Nigranum Moth

Olethreutes nigranum
view caption 		Olethreutes nigranumOlethreutes nigranumOlethreutes nigranum
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Taxonomy
Superfamily:
Tortricoidea		 Family:
Tortricidae		Subfamily:
Olethreutinae		Tribe:
Olethreutini		P3 Number:
51a0568		 MONA Number:
2800.00		 Other Common Name:
Dark Olethreutes
Comments: Olethreutes is a large genus with over 130 recognized species worldwide. North America has around 80 recognized species, with at least 37 species occurring in North Carolina. Some species are very difficult to identify due to interspecific similarities in color and forewing pattern and only subtle differences in genitalia (Gilligan et al., 2008). In many instances, knowledge of the host plant is essential for a confident determination. All of the Nearctic species are leaf-tiers or leaf-rollers on deciduous trees and shrubs.
Identification
Field Guide Descriptions: Beadle and Leckie (2012)Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLD                                                                                 
Adult Markings: Olethreutes nigranum has an array of phenotypes that range from specimens with a prominent black band along the inner margin, to individuals with the band lacking. Gilligan et al. (2008) noted that the forewing pattern is constant, but variation in the degree that the black coloration is expressed produces many different phenotypes. The areas that surround the larger patches and the median fascia often have a pinkish to reddish coloration or wash, which is helpful for identifying this species. The most easily recognized form, including the one that prevails in North Carolina, has a heavy suffusion of black on the thorax. The black suffusion continues as a broad, diffuse band along the inner margin that abruptly narrows and terminates in the subtornal region. Less intense darker dusting is also sometimes present near the middle of the costa and in the subterminal region of the wing. Many specimens can have lighter dusting that can reveal some of the underlying patterning, while others may have little or no dusting. When exposed, the color of the medial fascia can vary from uniformly brown or olive green to dark reddish brown at the costa and inner margin.

Gilligan et al. (2008) noted that O. clavana often has black dorsal shading, but it is usually less developed. This species tends to be a little smaller and lacks any of the pink to reddish coloration that is common in O. nigranum. In addition, the basal half of the costa has a series of pale strigulae that are often partially fused to form a zone of pale wash that is absent on O. nigranum. The genitalia of the two species are very similar (see below).
Wingspan: 17-22 mm (Heinrich, 1926).
Forewing Length: 7.5-10.5 mm (Gilligan et al., 2008).
Adult Structural Features: Gilligan et al. (2008) have illustrations of the male and female genitalia. They authors note that the male genitalia of O. clavana and O. nigranum are virtually indistinguishable, although the spines on the medial margin of the neck cavity are purported to be a little longer in O. nigrana (Miller, 1979). In both cases the digitus arises near the cucullus. Both species lack a signum, but subtle differences in sculpturing can be observed in the sterigmata.
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae are leaf tiers on maples, and rarely on other species, but details of the life history are sparse. Jeff Niznik found a larva in a leaf tie on Florida Maple on 23 April, and the adult emerged on 14 June. The larvae had a dull yellowish-green body with a jet black head and prothoracic shield. John Petranka also found a larva with a bright green body on Florida Maple on 12 April. It produced an adult on 21 May.
Distribution in North Carolina
Distribution: Olethreutes nigranum is found in eastern North America and is generally found in areas with cool climates. The range extends from Maine and other New England states westward through southern Quebec and southern Ontario to Illinois and Missouri, then southward to Tennessee, North Carolina, Virginia, West Virginia, Maryland, Pennsylvania and New York. As of 2024, our records are all from the Piedmont and from both lower and higher elevations in the Blue Ridge.
County Map: Clicking on a county returns the records for the species in that county.
Olethreutes nigranum
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: The adults have been found from April through August in different areas of the range, with a seasonal peak typically from June through August. As of 2024, our records extend from late-July through early-September, with most from late-July and early August. Populations in North Carolina are univoltine.
Habitats and Life History
Habitats: Local populations are commonly associated with mesic hardwood forests with maples.
Larval Host Plants: The larvae feed on deciduous hardwoods, with maples appearing to be the primary hosts (McDunnough, 1942; MacKay, 1959; Prentice, 1965; Miller, 1979; Godfrey et al., 1987). The reported hosts include Silver Maple (Acer saccharinum), Sugar Maple (A. saccharum), hickories (Carya; Miller, 1979) and American Basswood (Tilia americana; MacKay, 1959). As of 2024, we have three rearing records that are all for Florida Maple (Acer floridanum). - View
Observation Methods: The adults are attracted to lights. More information is needed on host use in North Carolina.
Wikipedia
See also Habitat Account for General Wet-Mesic Hardwood Forests
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR [S2S3]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments:

 Photo Gallery for Olethreutes nigranum - Variable Nigranum Moth

Photos: 16

Recorded by: John Petranka on 2024-05-21
Orange Co.
Comment: A reared adult from a larva that was collected on 4/11/24 from an Acer floridanum leaf tie, and was reared at room temperature. A well-developed pupa was photographed on 5/2/24 and the adult eclosed on 5/21/24 (see companion photos of the larva and pupa).		Recorded by: John Petranka on 2024-05-21
Orange Co.
Comment: A reared adult from a larva that was collected on 4/11/24 from an Acer floridanum leaf tie, and was reared at room temperature. A well-developed pupa was photographed on 5/2/24 and the adult eclosed on 5/21/24 (see companion photos of the larva and pupa).
Recorded by: John Petranka on 2024-05-21
Orange Co.
Comment: A reared adult from a larva that was collected on 4/11/24 from an Acer floridanum leaf tie, and was reared at room temperature. A well-developed pupa was photographed on 5/2/24 and the adult eclosed on 5/21/24 (see companion photos of the larva and pupa).		Recorded by: John Petranka on 2024-05-20
Orange Co.
Comment:
Recorded by: John Petranka on 2024-04-12
Orange Co.
Comment: A larva that was collected on 4/11/24 from an Acer floridanum leaf tie, and was reared at room temperature. A well-developed pupa was photographed on 5/2/24 and the adult eclosed on 5/21/24 (see companion photos).		Recorded by: John Petranka on 2024-04-12
Orange Co.
Comment:
Recorded by: John Petranka on 2024-04-12
Orange Co.
Comment: A reared adult from a larva that was collected on 4/11/24 from an Acer floridanum leaf tie, and was reared at room temperature. A well-developed pupa was photographed on 5/2/24 and the adult eclosed on 5/21/24 (see companion photos of the larva and adult).		Recorded by: John Petranka on 2024-04-11
Orange Co.
Comment:
Recorded by: John Petranka on 2024-04-11
Orange Co.
Comment: 		Recorded by: Jim Petranka and Becky Elkin on 2023-07-27
Buncombe Co.
Comment:
Recorded by: Jeff Niznik on 2023-04-23
Orange Co.
Comment: Larva found in leaf tie on Acer floridanum, adult emerged June 14.		Recorded by: Jeff Niznik on 2023-04-23
Orange Co.
Comment: Larva found in leaf tie on Acer floridanum, adult emerged June 14 (see companion photo of larva from 2023-04-23).
Recorded by: Jeff Niznik on 2023-04-23
Orange Co.
Comment: Larva found in leaf tie on Acer floridanum, adult emerged June 14 (see companion photo of larva from 2023-04-23).		Recorded by: John Petranka on 2022-08-08
Watauga Co.
Comment:
Recorded by: John Petranka on 2022-08-08
Watauga Co.
Comment: 		Recorded by: Merrill Lynch on 2009-07-14
Watauga Co.
Comment: