Upright webspinning sawfly

Lateral view of mature
larva, on ponderosa pine. — Lateral view of mature larva, on ponderosa pine. Dion Manastyrski Centre de foresterie du Pacifique, Victoria (Colombie-Britannique) / Pacific Forestry Centre, Victoria, British Columbia

Scientific name: Acantholyda verticalis (Cresson)
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Pamphiliidae

Distribution

Alberta, British Columbia

This species occurs throughout central and southern British Columbia; it also extends to Alberta and to California.

Damage, symptoms and biology

Acantholyda verticalis is a relatively uncommon innocuous solitary defoliator.

Mature larva up to 18 mm long. Head, light tan with a pair of seven segmented antennae and rows of brown spots in two patches over the crown. Body, yellowish green with prominent purplish brown middorsal, midventral and spiracular stripes; yellow subspiracular stripes. A pair of jointed appendages occur at the posterior end.

This species overwinters as a prepupal larva in earthen cells. Adults emerge in spring or early summer. Larvae construct silken webs and are active from June to July. Mature larvae drop to the soil in late July to August and construct earthen cells.