Stigmella intermedia
(Braun, 1917) Wilkinson et al., 1979
pygmy leaf-mining moth
Stigmella intermedia is a minute in the , characterized by a wingspan of only 3–3.5 mm. The is known from the Nearctic region, with records from Ohio, Arkansas, Kentucky, Ontario, and Vermont. It is a whose feed on sumac species (Rhus typhina and Rhus aromatica), creating distinctive linear mines with broad blackish . The species typically produces two per year, with larvae maturing in July and , though occasionally a third generation occurs.
Pronunciation
How to pronounce Stigmella intermedia: /stɪɡˈmɛl.ə ˌɪn.tərˈmiː.di.ə/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
are extremely small with wingspans of 3–3.5 mm, requiring microscopic examination for identification. The is distinguished from other Stigmella by ; males have diagnostic valvae and structures, while females exhibit characteristic signum and corpus bursae features. are bright green and create leaf mines on sumac with a loosened that changes from bright green to yellowish as the mine matures. The broad blackish , nearly as wide as the mine itself, is a distinctive feature of the larval mine.
Images
Habitat
Associated with stands of staghorn sumac (Rhus typhina) and fragrant sumac (Rhus aromatica), occurring in open woodlands, forest edges, old fields, and disturbed areas where these plants grow.
Distribution
Nearctic region: recorded from Ohio, Arkansas, Kentucky, and Ontario (Canada), with additional records from Vermont (USA).
Seasonality
Primarily , with two per year: mature in July and overwinter to pupate the following spring. A partial third generation may occur in some years.
Diet
are feeding internally on leaves of Rhus typhina (staghorn sumac) and Rhus aromatica (fragrant sumac). do not feed; their mouthparts are reduced or non-functional.
Host Associations
- Rhus typhina - obligate larval staghorn sumac; primary for leafmining
- Rhus aromatica - obligate larval fragrant sumac; secondary for leafmining
Life Cycle
are laid on leaves. hatch and immediately enter the leaf tissue, mining between the upper and lower while feeding on mesophyll. The larval stage creates a linear blotch mine with characteristic patterning. Larvae are very bright green. Mature larvae exit the mine to pupate, typically in soil or leaf litter. occurs in spring for larvae. The is partially to with occasional trivoltine .
Behavior
are , feeding entirely within leaf tissue. The loosened of the mine may provide some protection from desiccation and . are to and are attracted to light.
Ecological Role
As a , the contributes to leaf damage on sumac , though are typically low enough that significant impact is unlikely. The species serves as for and , though specific records are not documented.
Human Relevance
No direct economic importance. The is of interest to and naturalists documenting microlepidopteran diversity. It may serve as an for intact sumac-associated .
Similar Taxa
- Stigmella multispicataAnother small Stigmella with similar size and leafmining habit, but associated with elm (Ulmus) rather than sumac; distinguished by and
- Stigmella castaneaefoliellaSimilar in the same , but specialized on Castanea (chestnut) rather than Rhus; distinguished by association and mine characteristics
- Other Stigmella species on RhusSeveral mine Rhus leaves; definitive identification requires examination of and precise mine