Moths of North Carolina

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View PDF	Bucculatricidae Members:	Bucculatrix Members:	4 NC Records

Bucculatrix sexnotata Braun, 1927 - No Common Name

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Taxonomy

Superfamily:
Gracillarioidea

Family:
Bucculatricidae

Subfamily:
[Bucculatriginae]

Tribe:
[Bucculatrigini]

P3 Number:
33a0048

MONA Number:
529.00

Comments: Bucculatrix is a large genus of small leaf-mining moths, with around 300 species worldwide. A total of 103 Nearctic species have been described, and many others will likely be described in the future. Braun (1963) covered 99 species in her monograph, and four additional Nearctic species have been described since then.

Identification

Field Guide Descriptions:

Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLD

Technical Description, Adults: Braun (1963, p. 99)

Technical Description, Immature Stages: Braun (1963)

Adult Markings: This is a tiny, dark brown to blackish moth with oblique, silvery streaks. The head has an orange-red to dark brown tuft. The following description is from Braun (1963). The face is shining yellowish white. The tuft is orange-red in front, and shades to dark brown behind. The eye-cap is small and silvery white. The antenna stalk is fuscous in the basal half with faintly paler annulations. It becomes paler in the outer half, where it either shades to white, or has a whitish tip (especially in the females). The thorax and forewing ground color are dark and almost black. The forewing has five short, silvery white streaks that terminate before reaching the midline of the wing. The costa has three posteriorly oblique streaks, including one that extends from the base of the costa to the fold, a second that begins just before the middle, and the last at three-fourths. Along the inner margin, there is a posteriorly oblique streak that begins at one-third, and a somewhat rectangular streak before the tornus. Each of these is a little anterior to the corresponding costal streak. In addition to these, there is a white spot at the apex that is followed by a patch of blackish scales that project into the cilia. From this, there is a faint line of dark scales through the cilia along the termen. The hindwing and cilia are brown. The legs are dark brown, and the posterior tibia has long dull ocherous hairs. The abdomen is dark brown above.

Wingspan: 7-7.5 mm (Braun, 1963)

Adult Structural Features: The male and female genitalia, along with associated scale tufts and patches, are distinctive and are described and illustrated by Braun (1963). The following are her verbatim descriptions. Males: harpe with an outer curved setose lobe, apex with short heavy setae; socii very large, finely setose; anellus slender, conical, sclerotized; aedeagus curving from broad base to slender apex; vinculum moderately broad, rounded anteriorly. Scale sac present. Females: ostium small, circular, opening into a shallow sinus, margined by a strongly sclerotized horseshoe-shaped structure, its arms gradually broadening and attaining the posterior margin of the sclerotized basal half of segment 8; a patch of dark specialized scales each side of ostium on intersegmental membrane projects slightly beyond the posterior margin of 7; on dorsal posterior margin of 7 a dense line of scales, shorter than the lateral scales (not shown on figure); signum the usual ring of spined ribs, spines long, with an occasional larger spine.

Adult ID Requirements: Identifiable from good quality photos of unworn specimens.

Immatures and Development: The larvae make very long, convoluted, thread-like mines in the leaves of several species of asters. The mine has a continuous, central frass line. The early portion of the mine often has tightly packed convoluted adjoining sections with dark-staining tissue around them that resembles a blotch. The later portion is more linear (Eiseman, 2019). Three instars are passed in the mine. The fourth and fifth instars feed exposed on the underside of the leaf where they create irregular eaten patches. The upper epidermis is not consumed and the larvae spin thin sheet-like cocoons on the leaf to molt (Braun, 1963; Eiseman, 2019). Molting cocoons that Jim Petranka observed at Mt. Mitchell were usually constructed at or near the midrib and at a junction with a side vein. They were often placed near the base of the leaf. The mature larvae are translucent and greenish, and it is not uncommon for a single leaf to have several mines. Braun (1963) noted that, along the Appalachian Trail at elevations between 5000 and 6000 feet in the Great Smoky Mountains, the mines are sometimes so plentiful on Eurybia divaricata as to shrivel the leaves and disfigure the plants. The pupation cocoon is slender, with six well-defined ridges. It is pale grayish brown, but occasionally whitish. Overwintering occurs in the pupal stage and the adults emerge the following spring.

Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.

Distribution in North Carolina

Distribution: Bucculatrix sexnotata is found in the eastern US and in southern Canada, where is occurs in Alberta, and from Ontario eastward to New Brunswick and Newfoundland. The range in the US extends from the northeastern states (Vermont; Massachusetts; New York) southward and westward to Ohio, Kentucky, Pennsylvania, and North Carolina. As of 2023, our two records come from high elevation sites in the Great Smoky Mountains and at Mt. Mitchell. Annette Braun discovered this species in the Smoky Mountains in 1953, and it has not been reported since then in North Carolina until its recent discovery at Mt. Mitchell.

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
Immature 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: The adults are commonly on the wing in July. Adults reared from larvae that were collected in August in North Carolina emerged in April the following year (Braun, 1963). Jim Petranka found larvae and molting cocoons in abundance in mid-August at Mt. Mitchell. Two adults emerged in late-March after overwintering in a refrigerator.

Habitats and Life History

Habitats: Leaf mines of this species were abundant along a high ridge in the Great Smoky Mountains between 5,000 and 6,000 feet where they fed solely on E. divaricata (Braun, 1963). They have also been found near the summit of Mt. Mitchell on Eurybia chorolepis. These host species is fairly common in the state and occupies a range of dry to moist forests and forest edges.

Larval Host Plants: The larvae feed on several species of asters (Eurybia and Symphyotrichum). The documented hosts include White Wood-aster (E. divaricata), Heartleaf Aster (S. cordifolium), New York Aster (S. novi-belgii), and Crooked-stem Aster (S. prenanthoides). In North Carolina, we have leaf mine records for White Wood-aster as well as the closely related Mountain Wood-aster (E. chlorolepis). - View

Observation Methods: The adults rarely visit lights, and many records are based on leaf mines or adults that were reared from mines. We recommend searching the leaves of E. divaricata or other fall asters during the late-summer or early fall months.

Wikipedia

See also Habitat Account for Aster Fields and Herb Layers

Status in North Carolina

Natural Heritage Program Status: [SR]

Natural Heritage Program Ranks: GNR SNR [S1S3]

State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.

Comments: Until recently discovered at Mt. Mitchell, B. sexnotata has not been recorded in North Carolina since 1953. There is a possibility that this species is a rare northern disjunct, but the distribution of its host plants suggests that it could be a lot more common. As with many of our smaller micros, more surveys need to be conducted in order to assess this species conservation status. Larval surveys probably offer the best means of obtaining this information.

Photo Gallery for Bucculatrix sexnotata - None

Photos: 7

	Recorded by: Jim Petranka on 2023-03-24 Yancey Co. Comment: One of two adults that were reared from Eurybia chlorolepis; mines on Aug. 17, 2022; pupae on Aug. 24, 2022; adults on March 23 and March 29, 2023 after overwintering in a refrigerator.		Recorded by: Jim Petranka on 2023-03-24 Yancey Co. Comment: One of two adults that were reared from Eurybia chlorolepis; mines on Aug. 17, 2022; pupae on Aug. 24, 2022; adults on March 23 and March 29, 2023 after overwintering in a refrigerator.
	Recorded by: Jim Petranka on 2023-03-24 Yancey Co. Comment: Two adults were reared from Eurybia chlorolepis; mines on Aug. 17, 2022; pupae on Aug. 24, 2022; adults on March 23 and March 29, 2023 after overwintering in a refrigerator.		Recorded by: Jim Petranka and Becky Elkin on 2022-08-17 Yancey Co. Comment: A leaf of Eurybia chlorolepis with seven mines.
	Recorded by: Jim Petranka and Becky Elkin on 2022-08-17 Yancey Co. Comment: A leaf of Eurybia chlorolepis with several mines.		Recorded by: Jim Petranka and Becky Elkin on 2022-08-17 Yancey Co. Comment: A backlit image of mines on Eurybia chlorolepis.
	Recorded by: Jim Petranka and Becky Elkin on 2022-08-17 Yancey Co. Comment: Two cocoons on the underside of a leaf.