Moths of North Carolina
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87 NC Records

Besma endropiaria (Grote & Robinson, 1867) - Straw Besma Moth

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Superfamily: Geometroidea Family: GeometridaeSubfamily: EnnominaeTribe: OurapteryginiP3 Number: 911323.00 MONA Number: 6884.00
Comments: This genus currently contains 7 species named from Central and North America, and additional neotropical species await description. Two species occur in North Carolina.
Species Status: Specimens from North Carolina have been sequenced and are similar to those from throughout the range. The species is only about 1.4% different from B. quercivoraria, perhaps indicating a more recent radiation. Interestingly, though Rupert (1944) defined the differences, they were considered conspecific by some authorities into the eighties (e.g., McGuffin, 1987).
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Rupert (1944); Forbes (1948)Technical Description, Immature Stages: Forbes (1948); Wagner et al. (2001)                                                                                 
Adult Markings: Both males and females are a pale translucent straw yellow with slightly darker yellow-brown antemedian and postmedian lines and a partial subterminal line. The wings are angled at vein M3, resembling the similarly pale yellow Lambdina fiscellaria, but the postmedian lines is more evenly curved or relatively straight rather than sharply bent. Size, wing-angulation, and pattern of lines are similar to that of Besma quercivoraria, but the lines tend to be darker in that species, the wings more opaque, and a dark discal dot is usually present (Forbes, 1948). There is also more sexual dimorphism in quercivoraria, with males typically heavily shaded with yellowish-brown in the subterminal area (Forbes, 1948). While males of the two species are relatively easy to distinguish, some pale forms of female quercivoraria may be impossible to separate from endropiaria, although most female quercivoraria possess a light sprinkling of yellow-brown or reddish scales, sharper lines, and a dark discal spot.
Wingspan: 30-35 mm (Forbes, 1948)
Adult Structural Features: The genitalia of both Besma species are quite similar but there are apparent differences in the valve tips and the female genitalia.
Structural photos
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The greenish caterpillar, with dorsal warts on A6 and reddish patches on either side of the head, is distinct (illustrated by Wagner et al., 2001)
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Most of our records come from the Low Mountains, but there are at least a few populations located in the eastern 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: Reported to have a single flight in the Northeast (Wagner et al., 2001), which also appears to be true for our Mountains. Our few records from the Piedmont, however, are also consistent with a single mid-summer flight (one aberrant record comes from November, however).
Habitats and Life History
Habitats: The majority of our records come from rich, mesic stands of hardwoods. In the Mountains, habitats include northern hardwoods, cove forests, and stands of riparian hardwoods. Our few Piedmont records come from monadnocks with extensive north-facing slopes.
Larval Host Plants: Polyphagous, reported frequently on Maple but also on Alder, Birch, and Oak (Wagner et al., 2001). Covell (1984) lists Sugar Maple as the host, which fits with the greater frequency of endropiaria occurring in the Mountains in North Carolina. At the one anomalous site where this species has been found in the Piedmont, a related species -- Southern Sugar Maple -- occurs in abundance. In general, the actual host plants used in the wild need more documentation.
Observation Methods: Adults come frequently to lights in appropriate habitat. Their response to baits is unknown but probably negative.
See also Habitat Account for Rich Wet-Mesic Hardwood Forests
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: G5 [S5]
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 fairly widespread in the Mountains, where it is associated with fairly common types of habitat. Too few Piedmont records exist to determine its status in that region, but within the state as a whole, it appears to be fairly secure.

 Photo Gallery for Besma endropiaria - Straw Besma Moth

Photos: 18

Recorded by: Jim Petranka and Becky Elkin on 2023-06-24
Buncombe Co.
Recorded by: David George on 2023-06-16
Avery Co.
Recorded by: Jim Petranka on 2023-06-04
Madison Co.
Recorded by: Jim Petranka on 2023-06-02
Madison Co.
Recorded by: Jim Petranka and Becky Elkin on 2022-06-07
Madison Co.
Recorded by: Ken Kneidel on 2022-05-27
Yancey Co.
Recorded by: Jim Petranka on 2021-06-04
Madison Co.
Recorded by: tom ward on 2021-05-30
Buncombe Co.
Recorded by: tom ward on 2021-05-27
Buncombe Co.
Recorded by: Ken Kneidel on 2020-06-14
Yancey Co.
Recorded by: Jim Petranka and Becky Elkin on 2019-06-07
Madison Co.
Recorded by: David George on 2019-05-27
Watauga Co.
Recorded by: Stephen Hall and Ed Corey on 2017-05-17
Surry Co.
Recorded by: Steve Hall and Bo Sullivan on 2016-06-15
Ashe Co.
Recorded by: B. Bockhahn, K. Kittelberger, P. Scharf on 2015-06-18
Avery Co.
Recorded by: Steve Hall and Ed Corey on 2015-05-16
Alleghany Co.
Recorded by: Vin Stanton on 2012-05-18
Buncombe Co.
Recorded by: SPH on 1992-11-22
Orange Co.
Comment: Determined by D.F. Schweitzer. The date for this specimen is far outside the normal flight period for this species. Whether this represents a valid date is uncertain. The site, at least, has other records for this species, all collected in June.