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Species Besma quercivoraria - Oak Besma - Hodges#6885

twig looking inch worm - Besma quercivoraria twig looking inch worm - Besma quercivoraria twig looking inch worm - Besma quercivoraria Oak Besma - Besma quercivoraria
Show images of: caterpillars · adults · both
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Geometroidea (Geometrid and Swallowtail Moths)
Family Geometridae (Geometrid Moths)
Subfamily Ennominae
Tribe Ourapterygini
Genus Besma
Species quercivoraria (Oak Besma - Hodges#6885)
Hodges Number
6885
Synonyms and other taxonomic changes
described in 1857 by Guenee, who originally placed it in genus Metanema
Explanation of Names
Specific name means "oak eater"
Size
Wingspan 27-41 mm (1)
Identification
Adult: sexually dimorphic - female forewing pale tan with fine straight PM line, scalloped subterminal line (sometimes absent), and sometimes diffuse gray spot near anal angle; male forewing has brownish-orange or gray shading beyond PM line; wing veins darker than ground color on all wings; black discal dot may be present or absent on forewing and hindwing; all wings have pointed projection mid-way along outer margin in both sexes

Larva: a twig mimic - body green, brown, or tan with conspicuous reddish or darkened thoracic and abdominal swellings; head reddish-brown, flattened and sloping; vertex somewhat lobed to either side, lobes often bearing pale triangular area, widest behind; second thoracic segment conspicuously swollen; second abdominal segment with small subspiracular and ventral warts; third segment bearing conspicuous lateral and dorsal swellings, and sixth segment with dorsal warts; subtle longitudinal wrinkle forward of spiracle
[adapted from description by David Wagner and Valerie Giles]
Range
across southern Canada (Newfoundland to British Columbia) and all of United States except California
Habitat
deciduous and mixed woodlands; adults are nocturnal and come to light
Season
adults fly from April to September in the south (1); May to August in Ontario; late May to July in Alberta
larvae present from May to October
Food
larvae feed on leaves of oak, elm, poplar, willow, White Spruce (Picea glauca) (1), and mostly Paper Birch (Betula papyrifera) in southern Canada
Life Cycle
two generations per year; overwinters as a pupa
See Also
McGuffin (1987) found no apparent morphological differences between adult Besma quercivoraria and B. endropiaria, but in eastern North America quercivoraria produces two annual broods and endropiaria produces one (Wagner et al, 2001).
Synaxis cervinaria forewing lacks scalloped subterminal line, wings veins are paler than ground color, and species occurs only in the west
Hemlock Looper (Lambdina fiscellaria) forewing lacks scalloped subterminal line and flies in the fall
Horned Spanworm forewing has double PM line and lacks subterminal line
Print References
Covell, p. 370, plate #53, 19 & 20 (1)
McGuffin, W.C. 1987. Guide to the Geometridae of Canada (Lepidoptera): II. Subfamily Ennominae, 4. 182 pp.
Wagner, D.L., D.L. Ferguson, T.L. McCabe, and R.C. Reardon. 2001. Geometroid Caterpillars of Northeastern and Appalachian Forests. 239 pp.
Internet References
Moth Photographers Group - range map, photos of larvea, living and pinned adults.
Maryland Moths - 4 live adult images showing variation in color and pattern (Larry Line, Maryland)
Caterpillars of Eastern Forests - caterpillar photo and description plus foodplants and seasonality (David Wagner and Valerie Giles, USGS)
3 pinned adult images showing variation in color and pattern (CBIF)
live adult images and flight season (Lynn Scott, Ontario)
species account including common name reference, habitat, flight season, description, larval foodplants, similar species, life history, distribution (Strickland Entomological Museum, U. of Alberta)
pinned adult image with date and location label (Bruce Walsh, Moths of Southeastern Arizona)
live adult image and date (Dave Morgan, Georgia)
presence in Florida; list (John Heppner, Florida State Collection of Arthropods)
distribution in Canada; list of provinces of occurrence (CBIF)
Works Cited
1.Field Guide to Moths of Eastern North America
Charles V. Covell, Jr. 2005.