Moths of North Carolina
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5 NC Records

Metanema determinata Walker, 1866 - Dark Metanema Moth

No image for this species.
Taxonomy
Superfamily: Geometroidea Family: GeometridaeSubfamily: EnnominaeTribe: AnagoginiP3 Number: 91a1192 MONA Number: 6820.00
Comments: One of three species in this genus that occur in North America north of Mexico (Pohl et al., 2016), with determinata the only one that has been recorded in North Carolina
Identification
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012)Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Forbes (1948); McGuffin (1987)Technical Description, Immature Stages: Forbes (1948); Wagner et al. (2001)                                                                                 
Adult Markings: A medium-sized, grayish-brown Geometrid with fairly broad, falcate forewings and angulate outer margins on both pairs of wings. The head, body and ground color of the wings is fairly dark gray. The wings are transversely striated with fine darker gray lines; the veins are contrastingly pale. Two pale yellow transverse lines run fairly straight across the wing, the second beginning just before the apex. Hindwings are similar in color and pattern.
Wingspan: 25-30 mm (Forbes, 1948)
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: Larvae are smooth, light brown twig mimics, variegated with gray, white and black mottling. Paler triangular or spade-shaped spots occur on the dorsal surface of the second three abdominal segments (see illustration and description in Wagner et al., 2001).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Recorded in North Carolina only in the New River drainage in the northern mountains
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
Flight Comments: Our records come from May and July, which is consistent with the two generations reported in the northern part of its range (Wagner et al., 2001)
Habitats and Life History
Habitats: Our records all come from riparian shorelines or wetlands where willows are common
Larval Host Plants: Stenophagous, feeding primarily on willows but also reported on poplars (Forbes, 1948; Wagner et al., 2001) - View
Observation Methods: Comes to light to some extent but to what extent has not been determined in North Carolina
Wikipedia
See also Habitat Account for Montane Shoreline Shrub Thickets
Status in North Carolina
Natural Heritage Program Status: W3
Natural Heritage Program Ranks: GNR [S3S4]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species is a wetland specialist and occupies what appears to be a fairly small range in North Carolina, probably the southernmost outlier of what could be a fairly extensive range along the New River. While we have only a small number of records, this species probably is at least locally common and could occur at other locations in the Mountains. More surveys of willow- or poplar-containing habitats are needed to determine its conservation status within the state.