Dose-dependent pheromone responses of Ips pini, Orthotomicus latidens (Coleoptera: Scolytidae), and associates in stands of lodgepole pine

We conducted four behavioral choice tests in stands of mature lodgepole pine in British Columbia, from 1988 to 1991, to determine the dose-dependent responses of Orthotomicus latidens (LeConte) and Ips pini (Say) to their respective pheromones. Dose-dependent responses were exhibited by I. pini to (-)-ipsdienol and lanierone, with trap catches directly proportional to pheromone release rates. We found differences in sex ratio of L pini in their responses to ipsdienol but not lanierone. There was no dose-dependent response exhibited by O. latidens to its pheromone, (+/-)-ipsenol, with or without the presence of the host kairomone, (-)-beta-phellandrene. The bark beetle predator, Enoclerus lecontei (Wolcott), showed a dose-dependent response to lanierone. Thanasimus undatidus (Say) was attracted to ipsenol in a dose-dependent fashion only when traps were also baited with beta-phellandrene. Neither T undatulus nor E. sphegeus (F.) exhibited dose-dependent responses to ipsdienol.