Weevils - Entomological Society of Canada

Comments. Wood (1979) has prepared a catalog of the North
American species. A key to the North American species appears in
Chamberlin (i939).
Platypus wilsoni Swaine
Figs.12,13
Platypus wilsoni Swaine, 1916:98 (holotype, Campbell River, B.C.;
CNC); Chamberlin 1939:112; Keen 1952:183; Chamberlin 1958:24,
33-34; Arnett 1960:L029; Wood I97l:394; Furniss and Carolin
1977:338;Wood 1979:2.
Description. Length 5.0-5.7 mm. Head densely granulatereticulate,
with dense, erect setae. Pronotum 1.4 times longer than wide,
widest just before base; surface smooth, with scattered, fine, impressed
points; posterior half with a ftne, impressed, longitudinal, median line in
female, surrounded by a very densely punctured oval area, the
punctured area absent in male. Elytra 2.5 times longer than wide; sides
parallel on posterior three-quarters, gradually converging to apex; apex
truncate, with lateral apical angles slightly dentate in female (Fig. 13) or
strongly produced in male (Fig. 12); striae impressed in regular rows,
with fine punctures; interstriae weakly convex, smooth.
Distribution. Southern British Columbia, south to California
and Idaho. British Columbia: Campbell River, Eberts, and Steelhead.
Comments. Adults of this unusual species are easily recognized
by the illustrations (Figs. 12,13) and by the characters given above.
They cannot be confused with those of any other Canadian species of
Coleoptera. In coastal British Columbia the adults attack timber from
midJuly to mid September. The male bores an entrance tunnel through
the bark for a short distance into the wood. When a female approaches
the entrance hole and identifies herself through chemical, auditory, and
tactile signals, the male backs out of the entrance tunnel to admit her.
Mating takes place while the male is on the bark surface and the female
protrudes the tip of her abdomen from the hole. After mating, the female
continues extending the gallery and lays eggs loosely in the tunnel in
clusters of about 20-40. The larvae move freely in the mines and feed on
the spores of an ambrosial fungus that the female has introduced into the
galleries. Larvae and adults overwinter in the logs. Larval development
requires a year or more. When full grown, the larvae excavate cells at
right angles to the main gallery and parallel to the grain of the wood;
pupation occurs in these cells. Young adults emerge from the parental
entrance hole. All species of coniferous trees, except Cupressinae, may
be attacked by this species. It is, howeve! rare in pine (Pinus spp.).
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