Moths of North Carolina
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View PDFNepticulidae Members: 1 NC Records

Stigmella rhamnicola (Braun, 1916) - No Common Name


Taxonomy
Superfamily: Nepticuloidea Family: NepticulidaeP3 Number: 160029.00 MONA Number: 74.00
Comments: Members of the genus Stigmella are a group of small leaf-mining moths that typically create linear mines, although a few species form linear-blotch or blotch mines. Newton and Wilkinson (1982) recognized 51 species in their revision on the North American fauna, and new discoveries have since raised the total to around 57 species. Almost all species are specialists and rarely use more than one genus of host plants. Host-specificity, mine characteristics, and genitalic differences are helpful in recognizing closely related forms that are externally similar.
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, BAMONATechnical Description, Adults: Braun, 1917; Newton and Wilkinson, 1982.Technical Description, Immature Stages: Braun, 1917; Newton and Wilkinson, 1982; Eiseman, 2019.                                                                                 
Adult Markings: The following is based on the description provided by Braun (1917) and Newton and Wilkinson (1982). This species has two seasonal morphs that are associated with the summer and overwintering generations. These morphs are similar in overall coloration and patterning, except that the tuft and collar are off-white in the summer generation versus dark-brown to blackish in the overwintering generation. The antenna is black and narrowly ringed with pale gray, while the eye-caps are creamy buff. The thorax is creamy buff, and the patagia dark brown. The forewing is brown, with the tips of the scales blackish. At the basal third of the wing there is a cream colored to buff fascia with its edges often indented by dark scales. At two-thirds of the wing length there is a somewhat shiny silvery fascia. The cilia are pale gray and whitish around the apex. The hindwings and cilia are gray. The front and middle legs are ocherous and somewhat shaded with gray, while the hind legs are predominantly gray. The abdomen is brown above and paler beneath. The off-white thorax is distinctive and helps to separate this species from all other Stigmella with two fasciae, except S. gossypii, which is restricted to southern Florida.
Wingspan: 4.2-5.6 mm for males; 4.6-5.6 mm for females (Braun, 1917; Newton and Wilkinson, 1982)
Adult Structural Features: Newton and Wilkinson (1982) provide detailed descriptions and illustrations of the genitalia, including a comparison of the summer and overwintering forms of this species that differ in certain aspects of the genitalia. These include the cornuti of the vesica in the males, and possibly the degree of sclerotization of the pectinations of the bursa copulatrix in the females. The genitalia of both generations differ from members of the S. prunifoliella group in the size of the aedeagus, the form of the uncus, the continuous transverse bars of the transtilla in the male, and in the spinose bases to the apophyses posteriores in the female.
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The egg is deposited on the underside of the leaf, and the hatchling makes a short contorted mine within a small area. The mine then extends as a fine, nearly straight line for a distance of about 1.5 cm. The larva then crosses to the upper surface, continuing as a winding linear mine for a distance of about 1.5 cm. The mine then suddenly expands into a broader tract or blotch that is 2-3 mm wide and about 2 cm long (Braun, 1917). The frass is initially deposited as a continuous black line, but often becomes a granular, zigzagging line in later stages (Eiseman, 2019). The larva is bright green. The last instar exits the mine and constructs a tawny cocoon that is often placed on the host plant.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Stigmella rhamnicola is found in southeastern and south-central Canada (Saskatchewan, Manitoba, Ontario, Quebec) and the eastern US, including Vermont, Massachusetts, Connecticut, Wisconsin, Ohio and North Carolina (Eiseman, 2019). This species uses buckthorns (Rhamnus spp.) as a host and its range appears to have expanded since the introduction and spread of several species of non-native Rhamnus in the US and Canada. There are now many records for mines on R. cathartica, which is widespread and invasive in many areas of the northern US and southern Canada.
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 are in flight from early summer through the fall. Local populations have two or three broods per year depending on the latitude. Braun (1917) observed three generations per year in Ohio, and the mines were most abundant in October. As of 2020, we have a single record of this species, an adult observed in early June in the Blue Ridge.
Habitats and Life History
Habitats: Populations in North Carolina probably use Carolina Buckthorn as a host. This species is uncommon to rare in Piedmont and Blue Ridge and is generally associated with forested habitats with soils that are not strongly acidic.
Larval Host Plants: Outside of North Carolina, Lanceleaf Buckthorn (Rhamnus lanceolata) appears to be one of the most important native host. However, S. rhamnicola is increasingly using Common Buckthorn (Rhamnus cathartica), which is an invasive species. Eiseman (2019) also lists Frangula spp. as hosts. Carolina Buckthorn (Frangula caroliniana) is the likely host in North Carolina given that Rhamnus spp. are very rare in the state.
Observation Methods: The adults occasionally visit lights. We also recommend searching for the leaf mines on Frangula caroliniana.
Wikipedia
See also Habitat Account for Rich Dry-Mesic Hardwood Forests
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR SU
State Protection:
Comments: We currently do not have sufficient information on the distribution and abundance of this species within the state to assess its conservation status.

 Photo Gallery for Stigmella rhamnicola - No common name

Photos: 2

Recorded by: Kyle Kittelberger, Brian Bockhahn on 2014-06-07
Avery Co.
Comment:
Recorded by: Kyle Kittelberger, Brian Bockhahn on 2014-06-07
Avery Co.
Comment: