|scientific name Pontania proxima |
common name Willow Redgall Sawfly
Deciduous wood forests, edges of marshes and on urban and ornamental willow (Salix).
Adults emerge in late spring, larvae present in summer.
Adults: Adult willow redgall sawflies are small - approximately 3.5-5 mm long. They are shiny, black and wasp-like. They have asymmetric mandibles - the left mandible markedly constricted near the middle. The ovipositor is as long as the hind tibia while the cerci are shortened. The metatibia and metatarsomeres (leg segments on the third segment of the thorax) are not flattened or only slightly, and are not grooved laterally. The antennal hollow is smooth without hairs and has a shiny appearance, with only a few hairs on the lower part. The pronotum is described as black, possibly with pale margins (Goulet 1992: 99 -111; Zinovjev and Smith 2000: 853).
Larvae: The larvae of the willow redgall sawfly are pale green in color with a dark head. They are small and caterpillar-like, reaching only 5mm in length. They have legs present on the thorax and prolegs on each abdominal segment (Philip and Mengersen 1989: 59).
Adults emerge in late spring, and females seek out suitable willows on which to lay eggs. The female inserts an egg and material that induces galling into leaf tissue (Nyman et al 2000: 526-533) where the egg hatches and the larva begins to eat the soft leaf tissue. The leaf produces a gall which is bean-shaped, smooth and emerges equally on both sides of the leaf. The gall may be green, red or yellow. A single larva feeds in the cavity of each gall. In mid summer the larva leaves the gall to drop to the ground where it pupates. A second brood emerges in late summer, and the fall larvae overwinter as pupae. Generally there are two generations per year, though some authors suggest that there is only one (Philip and Mengersen 1989: 59).
Not endangered or of any economic consideration.
Leaves of willow (Salix) only.
Canadian prairies, eastern North America.
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