Moths of North Carolina
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View PDFGelechiidae Members: Dichomeris Members: 9 NC Records

Dichomeris bilobella (Zeller, 1873) - Bilobed Dichomeris

Dichomeris bilobellaDichomeris bilobellaDichomeris bilobella
Taxonomy
Superfamily:
Gelechioidea		 Family:
Gelechiidae		Subfamily:
Dichomeridinae		P3 Number:
59a0547		 MONA Number:
2291.00
Identification
Field Guide Descriptions: Beadle and Leckie (2012)Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Hodges (1986)                                                                                 
Adult Markings: Dichomeris bilobella and D. setosella are two closely related species that have very similar patterning and coloration on the forewings. The basal half has a dull, pale-yellow wash except for a conspicuous dark mark along the inner margin. The mark begins basally as a roughly triangular-shaped feature that contracts posteriorly to a narrow neck before expanding again into a broad, weakly curved, diagonal bar that projects towards the costa. The bar terminates before reaching the costa and is followed posteriorly by a wide zone of grayish to grayish-black wash in the post-medial area. Within this is a small black spot at the end of the cell that is bordered basally and distally to varying degrees with pale-yellow scales. The grayish zone is followed by a narrow, pale-yellow, transverse line. The line can vary from straight to wavy, with it most commonly being wavy in the medial area, and in most specimens tends to bend towards the apex near the costa. The subterminal portion of the forewing has a similar grayish to grayish-black wash, but is often a shade darker than that in the postmedial region. A line of dark dots is present at the base of the termen, with the dots having varying degrees of yellow scaling posteriorly. The prominent dark mark on the basal half of the wing extends to the inner margin.

North Carolina specimens are best identified using either genitalia, size, or the morphology of the labial palps. For a large series of specimens that have been identified using genitalia (J.B. Sullivan, pers. comm.), the wing length of D. bilobella in North Carolina typically varies from 8-9 mm versus 6-7 mm for D. setosella. The scaling on the second segment of the labial palps is also diagnostic (Hodges, 1986), with D. setosella having a strong ventral tuft at the apex that projects forward. In contrast, D. bilobella lacks a prominent ventral tuft and has scales on the ventral side that are more or less appressed to the second segment. The most conspicuous scaling is on the dorsal surface. Worn specimens of D. setosella may not have an obvious projecting tuft and can cause confusion. Another feature that is helpful is the width of the third palp segment. It is much wider in D. bilobella and about twice the width of that of D. setosella (J.B. Sullivan, pers. comm.).

Dichomeris vindex is a second species that is very similar to both D. bilobella and D. setosella and is best identified by using either genitalia, or by examining technical features such as the color of the scale tuft arising from the mesothoracic anepistemum in the male. Hodges (1986) noted that in D. setosella, the pale-yellow transverse line at two-thirds the wing length usually is slightly waved medially and angled slightly toward the base on the costal margin. In D. vindex this line is straight medially and angled slightly toward the apex on the costal margin. In D. bilobella the line is waved medially and often more broadly angled toward the apex. As of 2025, D. vindex has only been found at a single site in Madison County and probably does not occur east of the Appalachians (Hodges, 1986).

Because external patterning on the forewing widely overlaps between all three species, specimens should be submitted with both a wing length measurement and a lateral view of the labial palps whenever feasible.
Forewing Length: 5.4-8.3 mm (Hodges, 1986); Typically from 8-9 mm for North Carolina specimens (J.B. Sullivan, pers. comm.).
Adult Structural Features: Hodges (1986) has illustrations of the male and female genitalia. Also see genitalia from North Carolina specimens below.
Genitalia and other structural photos
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: The larvae feed on goldenrods and asters and either fold or roll the leaves of the host plant. Local populations appear to be univoltine in most areas of the range. Loeffler (1994) reported that the youngest larvae of this and other summer-feeding Dichomeris species are incapable of folding or rolling leaves. Hatchlings of species other than D. bilobella initially moved into hiding places then eventually spun silk mats that were commonly placed along the leaf midrib. The larvae lived and fed beneath the mats and expanded these with time, which caused the leaf to fold over the leaf mat. Larvae of D. bilobella deviated from this general pattern and did not spin mats. Instead, they initially fed between the developing leaves of the terminal bud, then soon formed tight folds along the margins of the larger terminal leaves that were expanding from the bud. The younger larvae often fed within the folds and skeletonized areas around the folds to form pits in the leaf, while older larvae often fed on portions of the entire leaf, beginning on the leaf margins and working inward. Individuals either remained in a single refuge for the entire summer, or left their refuge and constructed new ones several times before overwintering. Overwintering occurred on the ground in winter refuges that were made from short folds on senescent leaves and were sealed at the ends. Braun (based on notes reported by Hodges, 1986) reared an adult from Solidago flexicaulis in Kentucky. The larva rolled the edge of a leaf to the upper surface and fed from either end of the roll. It was collected on 9 May, and the adult emerged on 10 June.

Loeffler (1994) conducted a comprehensive study of host use by this and other Dichomeris species in the Northeast. Adults of D. bilobella in New York appeared in July, which is later in the year than other Dichomeris species that were studied. She was unable to find young larvae in the fall, but young larvae that were 2-3 mm long and probably second instars appeared in large numbers In late-April. These reached their final instars by mid- to late-June.

The final instar larvae are 15-17 mm long and have a pale-green abdomen with a series of pea-green stripes that converge at the abdomen tip to produce a dark-brown, V-shaped pattern (Loeffler, 1994).The lower portions of the lateral stripes become nearly black on the metathorax. The head, prothorax, and mesothorax are black except for a series of white patches on the posterior margin of the latter.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Hodges (1986) noted that D. setosella, D. bilobella, and D. vindex (a more northern species) have commonly been misidentified or confused and many records are unreliable. He reported this species to occur from Nova Scotia, southern Quebec and Ontario southward to Maryland, and westward to Minnesota, Missouri, and eastern Kansas. Current records indicate that the range extends at least as far south as Oklahoma, Arkansas and North Carolina. As of 2025, all of our records are from the Blue Ridge, except for a single specimen from near the coast that was identified using genitalia and palp morphology.
County Map: Clicking on a county returns the records for the species in that county.
Dichomeris bilobellaAlamance Alexander Alleghany Anson Ashe Avery Beaufort Bertie Bladen Brunswick Buncombe Burke Cabarrus Caldwell Camden Carteret Caswell Catawba Chatham Cherokee Chowan Clay Cleveland Columbus Craven Cumberland Currituck Dare Davidson Davie Duplin Durham Edgecombe Forsyth Franklin Gaston Gates Graham Granville Greene Guilford Halifax Harnett Haywood Henderson Hertford Hoke Hyde Iredell Jackson Johnston Jones Lee Lenoir Lincoln Macon Madison Martin McDowell Mecklenburg Mitchell Montgomery Moore Nash New Hanover Northampton Onslow Orange Pamlico Pasquotank Pender Perquimans Person Pitt Polk Randolph Richmond Robeson Rockingham Rowan Rutherford Sampson Scotland Stanly Stokes Surry Swain Transylvania Tyrrell Union Vance Wake Warren Washington Watauga Wayne Wilkes Wilson Yadkin Yancey
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge 		Image showing flight dates by month for High Mountains greater than 4,000 feet, Low Mountains, Piedmont, and Coastal Plain: adults.
Flight Comments: Hodges (1986) reported that the adults fly from mid-May until late August, which is consistent with our records from North Carolina.
Habitats and Life History
Habitats: This species is unusual in preferring forests with goldenrods and asters more so than woodland edges and large open fields (Loeffler, 1994). In New York and vicinity, Loeffler (1994) noted that the larvae can reach high densities in wooded hillsides where Bluestem Goldenrod and other hosts were abundant. It was rarely encountered in large, open fields where other Dichomeris species were found. As of 2025, most of our records are from forested sites or semi-wooded residential neighborhoods.
Larval Host Plants: Loeffler (1994) conducted a comprehensive study of host use by this and other Dichomeris species in the Northeast that use goldenrods and asters and documented the following hosts: White Wood-aster (Eurybia divaricata), Bigleaf Aster (Eurybia macrophylla), Tall Goldenrod (Solidago altissima), Cutleaf Goldenrod (S. arguta), White Goldenrod (S. bicolor), Bluestem Goldenrod (S. caesia), Canada Goldenrod (S. canadensis), Zigzag Goldenrod (S. flexicaulis), Giant Goldenrod (S. gigantea), Early Goldenrod (S. juncea), Gray Goldenrod (S. nemoralis), Wrinkle-leaf Goldenrod (S. rugosa), Heartleaf Aster (Symphyotrichum cordifolium), White Panicle Aster (S. lanceolatum), Calico Aster (S. lateriflorum) and Wavyleaf Aster (S. undulatum. Charley Eiseman also has a record on BugGuide for White Wood-aster (Eurybia divaricata). As of 2025, we do not have any feeding records from North Carolina. - View
Observation Methods: The adults are occasionally found at lights, and the larvae can be found in leaf folds on goldenrods and asters. More information is needed on host use and the larval life history for North Carolina populations.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks:
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments:

 Photo Gallery for Dichomeris bilobella - Bilobed Dichomeris

Photos: 6
Dichomeris bilobella
Recorded by: Merrill Lynch on 2025-08-08
Watauga Co.
Comment: 		Dichomeris bilobella
Recorded by: Emily Stanley on 2025-04-25
Buncombe Co.
Comment:
Dichomeris bilobella
Recorded by: Owen McConnell on 2024-05-23
Graham Co.
Comment: 		Dichomeris bilobella
Recorded by: Morgan Freese on 2022-07-27
Buncombe Co.
Comment:
Dichomeris bilobella
Recorded by: tom ward on 2021-08-29
Buncombe Co.
Comment: 		Dichomeris bilobella
Recorded by: B. Bockhahn, K. Kittelberger, P. Scharf on 2015-06-18
Avery Co.
Comment: