Host selection behavior of bark beetles (Coleoptera: Scolytidae) attackingPinus ponderosa, with special emphasis on the western pine beetle,Dendroctonus brevicomis

摘要: Detection of weakened hosts from a distance by bark beetles through olfaction was investigated in field experiments. No significant numbers Scolytidae were attracted to anaerobically treated pine bolts, stem disks, or sugar and ponderosa including phloem. Treatment living trees with cacodylic acid induced attacks byDendroctonusbrevicomis, D. ponderosae, Ips latidens, Gnathotrichus retusus, andPityophthorus scalptor, beginning two weeks after treatment. There no difference between landing rates ofD. brevicomis andD.ponderosae on screened controls. increase ofG. retusus andI. because both species had penetrated the screen produced pheromones. Tree frilling alone did not rate beetles. Freezing lower trunk dry ice significantly brevicomis, G. orI. latidens trees, whereas unscreened frozen attacked all four species. higher byD. I.paraconfusus, I. orHylurgops subcostulatus evidencing symptoms severe infection root pathogenVerticicladiella wagenerii, than symptornless trees. These experiments show thatD. paraconfusus, I.latidens, andG. land, apparently indiscriminately, healthy stressed hosts. Thus, these host discrimination must occur prior sustained feeding.