Moths of North Carolina
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41 NC Records

Grammia arge (Drury, 1773) - Arge Moth


Taxonomy
Superfamily: Noctuoidea Family: ErebidaeSubfamily: ArctiinaeTribe: ArctiiniP3 Number: 930240.00 MONA Number: 8199.00
Comments: One of 36 species in this genus that occur in North America (Schmidt, 2009), nine of which have been recorded in North Carolina. Included along with G. doris in subgenus Mimarctia, characterized by their completely pale costal cells as well as other features (Schmidt, 2009).
Species Status: Molecular analysis of five populations of arge formed a discrete cluster with low divergence. A 4.9% minimum interspecific difference separates arge from doris, the species of Grammia with the greatest similarity (see Fig. 133 in Schmidt, 2009). While these results indicate that arge is fairly homogeneous, we have noted variations both in the male valves and in the hindwing color and spot size that need further exploration.
Identification
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, BAMONATechnical Description, Adults: Forbes (1960); Schmidt (2009)Technical Description, Immature Stages: Forbes (1960); Wagner (2005)                                                                                 
Adult Markings: A pale, pinkish-cream colored Tiger Moth, with the black markings on the forewings reduced to narrow streaks and wedges. The cream-colored costal cell distinguishes arge from all other Grammia except for doris. Grammia arge and doris are very similar but Schmidt (2009) gives the following features of the forewing as diagnostic of arge: a broader pale band overlying vein C1 and the postmedian bent at an acute angle, meeting the costa obliquely rather than at a right angle or more obtusely as in doris. Schmidt further noted that the pale line along vein A1+2 is partially or entirely fused with the broad cream band running along the inner margin, whereas in doris it runs completely within the long black streak that runs just inward from the marginal pale band (see Schmidt's (=Neoarctia's) comments in iNATURALIST at https://www.inaturalist.org/observations/15377769#activity_identification_44104834).

The hindwings are usually pinkish white in arge but more completely pink, orange, or salmon in doris (Forbes, 1960). However, some of our specimens of arge also have salmon colored hindwings. A more reliable difference is that the black spots on the hindwing are usually smaller in arge than in doris and if larger, then those in the subterminal area are typically split by lines of the pink ground color, particularly along veins C2 and A1+2; in doris the spots are both large and undivided (Schmidt, 2009).
Forewing Length: 18.3 mm, males; 23.8 mm, females (Schmidt, 2009)
Adult Structural Features: Schmidt (2009) describes and illustrates several differences distinguishing male arge from doris. In arge, the distal portion of the valve is gradually tapered and has rounded apex; the caudoventral margin is slightly concave. In doris, the distal portion of valve is narrow, elongate, and crescentic. In specimens we have examined (see Structural Features) the valves appear to be more curved than shown in Schmidt's illustration for arge, but not as narrow as in doris.
Structural photos
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: Larvae are grayish purple to charcoal with prominent mid-dorsal and sub-dorsal white stripes (Forbes, 1960; Wagner, 2005). Setae are generally softer than in other Grammia. Larvae of G. doris are similar but the pale stripes are narrower and the sub-dorsal lines broken into separate spots.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Occurs over most of the state but records are missing from the Outer Banks and other barrier islands and from the High 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: Two generations exist over most of the East (Wagner, 2005), which appears to be true for both the Piedmont and Coastal Plain in North Carolina. However, there may just be a single flight in the Mountains.
Habitats and Life History
Habitats: Schmidt (2009) states that "Grammia arge is often a common species of dry woodlands, meadows, pastures, and grasslands." Wagner (2005) also lists dunes, sand plains, and waste lots. Our records come from a variety of primarily open areas, including Longleaf Pine sandhills, diabase barrens, and river and lake shorelines. However, we do not have any records from the dune grasslands of barrier islands.
Larval Host Plants: Members of this genus are highly polyphagous, feeding on a wide range of herbaceous plants, with Dicots possibly preferred (Schmidt, 2009). Brimley (1938) mentions that Chenopodium is used in North Carolina.
Observation Methods: Comes to blacklights, but usually just as single individuals. The mouthparts are non-functional (Singer, 2000, cited in Schmidt, 2009), so it does not come to bait.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: G5 [S4]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: Occurs in a variety of habitats across the state but appears to be fairly sparsely distributed. Probably secure, but more needs to be learned about its distribution and habitat requirements.

 Photo Gallery for Grammia arge - Arge Moth

Photos: 16

Recorded by: Jim Petranka and Becky Elkin on 2020-08-22
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-06-21
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2018-09-06
Madison Co.
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Recorded by: Ken Kneidel on 2018-08-11
Yancey Co.
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Recorded by: Ken Kneidel on 2018-08-11
Yancey Co.
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Recorded by: Ken Kneidel on 2018-08-11
Yancey Co.
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Recorded by: Jim Petranka and Becky Elkin on 2013-08-12
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2013-08-12
Madison Co.
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Recorded by: Paul Scharf on 2010-08-17
Warren Co.
Comment: Confirmed via specimen by Bo Sullivan
Recorded by: FKW on 2009-09-10
Gates Co.
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Recorded by: Steve Hall on 2002-05-16
Cumberland Co.
Comment: Male; wingspan = 4.0 cm; forewing length = 1.9 cm
Recorded by: J.B. Sullivan and L. Deutschman on 2001-08-17
Haywood Co.
Comment: Collected at 2900’
Recorded by: JBSullivan & LDeutschman on 2001-08-15
Swain Co.
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Recorded by: J.B. Sullivan on 2001-06-25
Haywood Co.
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Recorded by: S. Hall on 2000-02-24
Moore Co.
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Recorded by: Steve Hall on 1992-05-31
Granville Co.
Comment: Found in grass