Heterarthrus nemoratus
(Fallén, 1808)
Late Birch Leaf Edgeminer Sawfly
Heterarthrus nemoratus is a Palearctic in the Tenthredinidae. The larvae are specialized leaf-miners that feed on birch leaves (Betula species), creating distinctive mines along leaf edges. are active during late spring and summer. The species has been introduced to North America, where established occur in Canada.
Pronunciation
How to pronounce Heterarthrus nemoratus: /ˌhɛtərəˈɑrθrəs ˌnɛməˈreɪtəs/
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Identification
Larvae produce blotch mines that begin at the leaf edge and expand inward, often with concentrated in one corner. Mines are distinguished from those of the earlier-emerging Heterarthrus wuestneii by their later seasonal occurrence and more marginal position. are small, dark with reduced wing venation typical of the .
Images
Habitat
Associated with birch woodlands and stands, particularly those containing Betula pendula, Betula pubescens, and related . Occurs in both natural forests and urban plantings where trees are present.
Distribution
Native to the Palearctic region, with records across Europe including Belgium. Introduced and established in western Canada (Alberta, British Columbia).
Seasonality
active from late May through July; larval mines appear from June onward, later than related .
Diet
Larvae feed as leaf-miners on birch (Betula) leaves.
Host Associations
- Betula - larval food plantprimary
- Betula pendula - larval food plant
- Betula pubescens - larval food plant
Ecological Role
As a leaf-miner, larvae create localized damage to birch foliage. levels are generally not sufficient to cause significant tree stress or mortality.
Human Relevance
Minor aesthetic concern in ornamental birch plantings due to visible leaf mines. Not considered a significant forestry pest.
Similar Taxa
- Heterarthrus wuestneiiAlso a birch leaf-miner, but emerges earlier in spring and produces mines that are more centrally located on leaves rather than marginal.
- Profenusa thomsoniAnother birch-feeding , but larvae are external feeders causing skeletonization rather than leaf-mining.