|scientific name Dichelonyx |
common name Chafers
Pastures, highlands or on subalpine conifers, often on roses or other flowers.
Adults usually collected in early summer from May to July, seldom later.
Species in this genus are of moderate size, rather elongate and cylindrical, varying from brown to dark green with or without metallic reflections (Downie & Arnett 1996: 684). Antennae with 7 to 10 segments, club with 3 segments, labrum located below clypeus, fifth abdominal sternite and propygidium (seventh abdominal tergum) separated by suture. Apical margin of terminal tarsomere deeply notched (Arnett et al. 2002: 54,56). Mentum almost square, somewhat convex, last article of labial palps subfusiform, that of the maxillary palps lightly securiform. Head square, eyes large body finely pubescent (Lacordaire & Chapin 1856: 242). Larvae C-shaped, head lacking stridulatory areas on mandibles or indistinct with patch of minute granules, large patch of closely set asperities on each side of raster (hairs on terminus of abdomen) (Böving & Craighead 1953: 53).
Most Dichelonyx adults are nocturnal to avoid predation as they feed on foliage since they are fairly large often brightly colored conspicuous beetles, however those that feed primarily on pollen are more often diurnal. Adults can be attracted to lights and are often observed at night flying near them and copulating (Arnett et al. 2002: 52, 59). Sometimes considered pest insects in forest nurseries because of the extensive defoliation they can cause with nocturnal feeding if large numbers are present as well as the attack of coniferous and hardwood seedling roots by the larvae.
Seem to occur sporadically sometimes in large numbers.
Larvae are fossorial grubs that eat roots of various herbaceous or woody plants, most Dichelonyx adults feed on foliage but some have become specialists on pollen or flowers (Arnett et al. 2002: 59).
29 species found generally distributed across Canada except Newfoundland and Yukon, south throughout the United States to Baja California, Mexico (Arnett et al. 2002: 59). In Alberta, primarily occurring in the south of the province but specimens of D. backi collected as far north as Edmonton
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