SEASONAL FLIGHT PATTERNS OF BARK AND AMBROSIA BEETLES (COLEOPTERA, SCOLYTIDAE) IN NORTHEASTERN OREGON

The abundance and phenology of scolytid beetles collected in multiple- funnel traps baited with the Douglas-fir beetle (Dendroctonus pseudots ugae Hopkins) pheromones frontalin, seudenol, MCOL, and ethanol in NE Oregon are reported. Other than D. pseudotsugae, Dendroctonus ponderos ae Hopkins, and Dendroctonus rufipennis (Kirby), a total of 17,612 bee tles from 44 species were collected between 5 May and 21 Sep 1993. Den droctonus brevicomis LeConte and Hylastes nigrinus (Mannerheim) were m ost abundant (comprising 44.5% and 31.7% of the total, respectively), followed by Pityophthorus confertus Swaine (8.5%), Dendroctonus valens LeConte (4.2%), Hylastes longicollis Swaine (3.4%), and Hylastes rube r Swaine (2.7%). Most species were rare; the combined number of indivi duals of the 26 least common species comprised <1% of the total. Pityo phthorus deletus LeConte and Pityophthorus grandis Black-man are repor ted from Oregon for the first time. Flight activity for most species b egan after a seasonal increase in temperature in mid-May and subsided by late July. Seasonal flight patterns are shown for the 14 most abund ant species. It is unknown how each species was affected by the lure, but ethanol may have been an important attractant for many species.