|scientific name Synaxis jubararia |
common name October Thorn
Deciduous and mixedwood forests and woodlands.
Adults fly throughout September
The October Thorn is one a several rather large geometrids that fly in the fall and have autumn-leaf colours of ochres and rust-brown. The discal spots are small and black but distinct; wings with a pointed protrusion at mid-margin.
Similar to the extremely variable Prochoerodes transversata, but the PM line joins the wing margin in a straight line, while in transversata it angles sharply near the apex toward the thorax. S. pallulata, which occurs in the Crowsnest Pass region, is very similar, but has heavier crosslines and darker mottling. No structural differences between jubararia and pallulata are known.
The marbled grey-brown larvae have a large dorsal hump on the thorax, and resemble twigs (Ives & Wong 1988). The egg likely overwinters, and adults are nocturnal and come to light.
Not of concern.
Larvae feed on deciduous shrubs, particularly willows (Salix) and alder (Alnus), also on birch (Betula), poplars (Populus) and dogwood (Cornus (McGuffin 1987).
Essentially a western species, but occurring east to central Saskatchewan, south to CA (McGuffin 1987).
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