Response of Eastern Larch Beetle (Coleoptera: Scolytidae) in Alaska to Its Natural Attractant and to Douglas-Fir Beetle Pheromones

Abstract

In tests conducted in the McKinley River drainage, Alaska, seudenol combined with α-pinene attracted the most eastern larch beetles, Dendroctonus simplex LeConte. The next most attractive treatments included tamarack log sections infested with either unmated female D. simplex or unmated female Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, Neither frontalin nor trans- verbenol with α-pinene was attractive. Addition of niethylcyclohexenone (MCH) to the seudenol + α-pinene treatment repressed its attraction by 83%. Sex ratios of simplex responding to logs infested with female simplex or pseudotsugae were equal or favored females, but favored males in the case of seudenol + α-pinene. Addition of MCH shifted the sex ratio in favor of females. Two other scolytid species, Orthotomicus caelatus (Eichhoff) and Ips perturbatus (Eichhoff), were trapped, but were too few to relate to treatments. Two species of clerids were caught on traps: Thanasimus undatulus Say and Thanasimus dubius (L.); the latter is a new Alaskan record.

Local and geographic variation in the pheromone blend of the spruce beetle, Dendroctonus Rufipennis Kirby (Coleoptera: Curculionidae)

“…Adding MCH bubble caps to the commercial lures completely inhibited their attractiveness to all three bark beetle species. These results are consistent with prior trapping experiments involving D. rufipennis (Holsten et al 2003), D. pseudotsugae Daterman 1995a, Ross andDaterman 1995b), and D. simplex (Baker et al 1977). The identical responses by these three bark beetle species are not surprising given that they are closely related and share some of the same aggregation pheromone components, including frontalin (all three species) and MCOL (D. rufipennis and D. pseudotsugae) (Symonds and Elgar 2004).…”

Host-Tree Chemistry Affecting Colonization in Bark Beetles

“…duplicatus Borden (1982) and Byers (1989b). and the following (Bakke, 1975;Baker et al, 1977;Lame et al, 1987;Borden et al, 1987;Byers et al, 1989bByers et al, , 1990aByers et al, , 1990bTeale et al, 1991;Carnacho et al, 1993).…”

Composition of Attractant Semiochemicals of North American Species of Dendroctonus Bark Beetles: A Review

“…The odor source utilized in field and laboratory experiments may be the substrate itself, its extracts, or air passed over the substrate or its concentrates [103,104,[107][108][109]. With Dendroctonus and other bark beetles, the substrates typically investigated as semiochemical sources have been live beetles [49,51,[110][111][112], crushed beetles [51,58,103,113,114], the alimentary tract [115][116][117][118], frass produced during mining [56,107,[119][120][121], individual gallery entrances [74,108,[122][123][124], whole infested or uninfested logs [125][126][127][128][129], and distilled or whole host tree resin [80,81,130,131]. Once natural sources of semiochemical attractants are identified, odorants are isolated from them typically by either direct solvent extraction of the material (in particular, the insects, their tissues, frass, host tissue, and resin [51,56,98,118]) or use of chemical adsorbents to concentrate organic molecules in the air surrounding or passed across the odor s...…”

“…For example, frontalin is an attractive pheromone component for 13 of the 14 species for which an attractive pheromone has been identified. Due to this overlap, cross-attraction among species is common [57][58][59]98,128,129,221]. Some degree of specificity may be conferred through differences among species in the effects of different combinations of compounds.…”