Weevils - Entomological Society of Canada

Description. Length 4.5-5.5 mm (head excluded). Body with
ventral surface, legs, and rostrum black; elytra and dorsal surface of
pronotum red or reddish brown to light yellow; head dull or shining,
usually black, sometimes red behind eyes. Surface of head with elongate
punctures between eyes; interpuncture spaces weakly elevated, carinate
at base of rostrum. Eyes strongly convex. Rostrum of both sexes
straight, more so in female, distinctly punctured, with 1 weakly
elevated, longitudinal median ridge; base longitudinally impressed in
front of eyes. Pronotum 1.1 times wider than long, widest at middle;
sides broadly arcuate, strongly converging to broadly rounded apex; disc
distinctly convex, with moderate, impressed punctures; interpuncture
spaces moderately shining, smooth. Elytra l-.3 times longer than wide,
at base 1.5-1.6 times wider than pronotum; strial punctures large;
interstriae L5-2.0 times wider than striae, smooth, with fine, erect,
scattered setae. Pygidium densely punctured.
Distribution. Ontario to British Columbia, south throughout
the United States to South Carolina in the east and Arizona and
California in the west. Evidently more common in the west. Alberta:
Calgary, Irving, Lethbridge, McMurray, Medicine Hat, Orion, Pincher
Creek, and Red Deer. British Columbia: Agassiz, Ashcroft, Boswell,
Bowser, Cawston, Colwood, Cottonwood, Courtenay, Cowichan Lake,
Creston, Elko, Galiano Island, Goldenstream, Kamloops, Langley,
Lillooet, Merritt, Mission, Mission Flats, Nelson, Nicola, Osoyoos,
Pavilion Lake, Peachland, Robson, Rolla, Royston, Saanich, Salmon
Arm, Sicamous, Soda Creek, Squamish, Steelhead, Summerland,
Trinity Valley, Vancouveq Vernon, Victoria, and Wellington. Manitoba:
Birds Hill, Carberry, 2Ikm north of Glenboro, Ninette, Onah, Pierson,
and Stockton. Ontario: Fort Erie, Ingolf, Nestor Falls, Ojibway, and St.
Catharines. Saskatchewan: Cut Knife, Cypress Hills, Fort Walsh,
Lebret, Oxbow Pike Lake, Saskatoon, St. Victor, Val Marie, and
Weyburn.
Comments. This species is commonly known as the rose curculio
and is an occasional pest of cultivated roses (ftoso species) as well as
blackberries and raspberries (Rubus species). The adults damage roses
by puncturing numerous holes in the flower buds, causing the blooms to
fail to develop. The larvae develop in the hips, feeding on the achenes.
Adults also puncture ripe blackberries and raspberries, causing them to
rot. Specimens of this species so strongly resemble those ofM. wickhomi
that identification is difficult if not impossible, unless one examines the
spiculum gastrale (Figs. 157 and t62).InM. bicolor, the lateral margin of
the spiculum gastrale (just at the expansion into the bifid process) bears
an acute, tooth-like process; the process is absent inM. wiclthumi. Other
characters given in the key to species are quite variable. (See discussion
under M. wiclzhami.) The lectotype of M. bicolor was designated by
Hamilton (1983b).
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