Moths of North Carolina
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1 NC Records

Ectoedemia occultella (Linnaeus, 1767) - Small Birch Leafminer Moth

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Taxonomy
Family:
Nepticulidae		P3 Number:
16a0095		 MONA Number:
47.00		 Other Common Name:
Large Birch Pigmy
Comments: As currently recognized, Ectoedemia occultella is a very wide-ranging species that is found from westernmost Europe eastward to Japan, and throughout northern North America. Populations in Europe and elsewhere in the Old World have diverged genetically from those in North America, but Nieukerken et al. (2016) considered the level of divergence to be insufficient to justify splitting this species into two or more species. North American populations were previously described as E. lindquisti (Freeman, 1962).
Identification
Field Guide Descriptions: Online Resources: MPG, iNaturalist, Google, BAMONA, GBIF, BOLD                                                                                 
Adult Markings: The following description is based on that of Nieukerken (1985). The head tuft of males is black and often mixed with brownish or brownish-yellow scales, and the collar is black. The thorax and ground color of the forewing are completely jet-black and less coarsely scaled than in other Ectoedemia species. There is a rather broad, almost straight dull white fascia near the middle of the wing that is sometimes slightly constricted in the middle. The cilia is also black and lacks a cilia-line. Females are similar, but the head tuft is yellowish to yellowish orange and sometimes mixed with fuscous, while the collar is yellow. The hindwing of the male has a relatively long white hair-pencil, and the underside of the forewing has a small elongate patch of narrow white scales along the costa that is often difficult to see. Females lack both of these features.

This species is easily distinguished from other Ectoedemia in eastern North America by its jet-black thorax, forewings, (except the fascia) and cilia, along with the absence of a cilia-line (Nieukerken, 1985). It can be separated from some of our Stigmella species by the medial white fascia (the fascia is typically found farther back on the wing on Stigmella) and by a collar that consists of hair-scales instead of lamellar scales as seen in Stigmella.
Wingspan: 5.7 - 8.4 mm for females; 5.1 - 7.5 mm for males (Nieukerken, 1985).
Forewing Length: 2.56 - 3.84 mm for females; 2.36 - 3.44 mm for males (Nieukerken, 1985).
Adult Structural Features: Nieukerken (1985) has detailed descriptions and illustrations of the male and female genitalia.
Immatures and Development: The larvae mine the leaves of birches and the eggs are typically laid on the underside of the leaf (rarely on the upperside). The mine is a large, nearly circular blotch that begins as a solid black blotch, then develops a light pale zone around the dark central area with time. The frass is black, and there can be two or more mines on a single leaf. The larvae are pale yellowish white with a light brown head. The penultimate stages have 12 black ventral plates (Nieukerken, 1985).




Distribution in North Carolina
Distribution: As currently recognized, Ectoedemia occultella is a very wide-ranging Holarctic species that is found from western Europe through Russia to as far east as Japan. It also occurs throughout much of northern North America. As of 2024, we have a single site record from a high elevation site in the Smokies that appears to be part of a southern disjunct population in the southern Appalachians.
County Map: Clicking on a county returns the records for the species in that county.
Ectoedemia occultella
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: This species appears to be univoltine throughout its range, but this has not been confirmed for North Carolina populations. In Europe, the larvae feed slowly from the end of June to as late as early November, then overwinter. The adults fly in May and June. As of 2024, our only record is for an occupied mine from late-September for a high-elevation site in the Smokies.
Habitats and Life History
Habitats: The larvae feed on birches (Betula spp.) and are generally associated with cool-temperate forests.
Larval Host Plants: The larvae have been documented in Europe feeding on a wide diversity of both native and cultivated birches. Our one record as of 2024 was for Yellow Birch (B. alleghaniensis). Eiseman (2022) also lists Sweet Birch (B. lenta) as a host.
Observation Methods: This species has strong affinities for northern forests and is best sought by searching for leaf mines at high-elevation sites in the Blue Ridge.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR[S1S2]
State Protection:
Comments: