Seasonal pheromone response by Ips pini in northern Arizona and western Montana, U.S.A

1 Populations of Ips pini (Say) in northern Arizona and western Montana, U.S.A., were studied to determine regional pheromone response and to evaluate seasonal shifts in that response. A range of enantiomeric blends of the attractant ipsdienol, alone and in the presence of the synergist lanierone, were tested during spring and summer seasons over several years. 2 Both populations were most attracted to high levels of ( R )-( – )-ipsdienol, and lanierone was highly synergistic. 3 A significant seasonal shift in pheromone response between spring and summer seasons was found in both regions in both years. Shifts resulted in a more specific preference for the pheromone treatment of 97% ( R )-( – )-ipsdienol with lanierone. 4 Several coleopteran insect associates of I. pini also displayed responses to the ipsdienol and lanierone treatments. Temnochila chlorodia (Mannerheim) (Trogositidae), Enoclerus sphegeus (F.) (Cleridae) and, to a limited extent, Lasconotus laqueatus (LeConte) (Colydiidae) were attracted to higher proportions of ( R )-( – )-ipsdienol with no apparent reaction to the presence of lanierone. Orthotomicus latidens (LeConte) (Curculionidae: Scolytinae) was strongly attracted to ( S )-( + )-ipsdienol with Enoclerus lecontei (Wolcott) (Cleridae), Pityogenes carinulatus (LeConte) (Curculionidae: Scolytinae) and Hylurgops porosus (LeConte) (Curculionidae: Scolytinae) demonstrating some preferences for the ( S )-( + )-enantiomer. However, lanierone was synergistic for E. lecontei and P. carinulatus , inhibitory for O. latidens , and produced no significant reaction for H. porosus . Elacatis sp. (Salpingidae, previously Othniidae) was attracted to the presence of ipsdienol but displayed no preference to the enantiomeric ratios of ipsdienol or the presence of lanierone.