Moths of North Carolina
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View PDFGeometridae Members: 55 NC Records

Nemoria bifilata (Walker, [1863]) - White-barred Emerald Moth


Taxonomy
Superfamily: Geometroidea Family: GeometridaeSubfamily: GeometrinaeTribe: NemoriiniP3 Number: 910626.00 MONA Number: 7045.00
Comments: One of 35 species in this genus that occur in North America (Ferguson, 1985), nine of which have been recorded in North Carolina. Ferguson (1969) included bifilata in his Bistriaria Species Group (VIII), which also includes bistriaria, rubrifrontaria, and mimosaria in North Carolina, as well as eight others in the West.
Species Status: Two subspecies have been described, of which we have only the nominate form; subpecies planuscula occurs in Texas (Ferguson, 1969, 1985).
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONATechnical Description, Adults: Forbes (1948); Ferguson (1969, 1985)Technical Description, Immature Stages: Ferguson (1985); Wagner (2005)                                                                                 
Adult Markings: A medium-sized Emerald with a reddish-brown spring form and a green summer form. The abdomen of the nominate subspecies has a dorsal white line which is unique among our species of this genus. The wings are striated with white, have narrow, sometimes obsolete white lines, and possess a narrow red terminal line.
Forewing Length: 10.5-13.5 mm, males; 12-14 mm, females (Ferguson, 1985)
Adult Structural Features: The foretibiae are red, as in N. lixaria and bistriaria, but lack the transverse white band found in those species (Ferguson, 1985). The male genitalia are distinctive, with differences in the valve tips easily visible by brushing away scales at end of the abdomen: the distal process of the costa is rounded in bifilata but sharply pointed in bistriaria (see Ferguson, 1985, for additional details and illustrations).
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: Larvae are light brown with a broken, blackish-brown dorsal stripe (Ferguson, 1985). The integument is coarsely pilose and the dorso-lateral processes characteristic of this genus are well-developed. The larvae of N. bistriaria are similar, but in bifilata the dorso-lateral processes are larger and more pointed and are not notched as in bistriaria (Ferguson, 1985). Additionally, the processes on the third abdominal segment are as large or larger than on the fourth segment, whereas they are equal or smaller in bistriaria.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: We have just one record from the Mountains. The rest come from the Coastal Plain or the eastern edge of the Piedmont.
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: Adults fly more-or-less continuously from late March to September, with most records coming from mid summer
Habitats and Life History
Habitats: With the exception of the three records from the Mountains and Piedmont, our records come entirely from dry-xeric oak woodlands, including Maritime Forests on the Barrier Islands and sandhills habitats further inland.
Larval Host Plants: Reared on Oak (Forbes, 1948), although Ferguson (1985) stated that the larvae appeared to be dwarfed on that diet (the species of oak was not mentioned). Ferguson also reared them successfully on Winged Sumac (Rhus copallina) but that species occurs across a wider range of habitats than does N. bifilata. In the dry-xeric habitats where bifilata primarily occurs in North Carolina, either xerophytic oaks or possibly Poison Oak (Toxicodendron pubescens) seem more likely.
Observation Methods: Comes well to blacklights but we have no records from bait or from flowers
Wikipedia
See also Habitat Account for General Dry-Xeric Hardwood Forests
Status in North Carolina
Natural Heritage Program Status: W3
Natural Heritage Program Ranks: G4 S3?
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: Nemoria bifilata appears to be uncommon throughout its range (Ferguson, 1985). In North Carolina, it appears to be associated with a narrow range of dry-to-xeric habitats, much of the range of which has been drastically reduced due to conversion to silviculture. Larval surveys are needed to determine the host plants used by this species, which should provide more information on its conservation needs.

 Photo Gallery for Nemoria bifilata - White-barred Emerald Moth

Photos: 3

Recorded by: Steve Hall and Bo Sullivan on 2021-04-07
Richmond Co.
Comment:
Recorded by: Steve Hall and Bo Sullivan on 2021-04-07
Richmond Co.
Comment:
Recorded by: Steve Hall and Bo Sullivan on 2021-04-07
Richmond Co.
Comment: One each in two traps, both located along an ecotone between a White Cedar swamp and a Pine-Scrub Oak Sandhill