|scientific name Besma quercivoraria |
common name Oak Besma
Deciduous and mixedwood forests.
Late May to early July peaking in mid June.
A thin-winged and finely marked geometrid. Ground colour pale tan, with a fine, straight PM line (sometimes absent on hindwing) and a scalloped (sometimes absent) subterminal line. Tiny black discal spot sometimes present on both. Fore and hindwings are characterized by a well-defined pointed projection mid-way along the margin. Lambdina fiscellaria is similar, but lacks the scalloped subterminal line (often more clearly visible on the underside), and flies in the fall.
Virtually identical to B. endropiaria in colour and pattern; according to Forbes (1948), endropiaria has translucent rather than opaque wings and lacks the discal spot. B. endropiariaB. quercivoraria are treated as the same species by McGuffin (1987) since there are no apparent morphological differences. In eastern North America there are however differences in broodedness, quercivoraria producing two annual broods and endropiaria one (Wagner et al. 2001).
The larvae are cryptic, and resemble twigs in colouration and texture. The pupa overwinters, and adults are nocturnal and come to light (Wagner et al. 2001). An uncommon moth in Alberta, usually only encountered in low numbers.
Not of concern.
Prentice (1963) reports the vast majority of larval collections in southern Canada from white birch (Betula papyrifera).
BC to Newfoundland, south to Fl and TX (McGuffin 1987).
Comments are published according to our submission guidelines. The EH Strickland Entomological Museum does not necessarily endorse the views expressed.