ELECTROANTENNOGRAM RESPONSES OF 2 POPULATIONS OF IPS-PINI (COLEOPTERA, SCOLYTIDAE) TO INSECT-PRODUCED AND HOST TREE COMPOUNDS

Electroantennograms in two populations of Ips pini (Idaho and New York) were very similar, even though previous work documented behavioral specificity and revealed that the populations produce different ratios of the enantiomers of the aggregating pheromone ipsdienol. The insect- and host-produced compounds tested evoked characteristic response curves in both populations. EAG amplitude was highest to ipsdienol and the aggregation inhibitor ipsenol. Among the other compounds tested, responses were generally higher to the beetle-produced odorants (linalool, verbenone, trans-verbenol) than to host terpenes (1-octanol, α-pinene). The antennal club and its sensory receptors are described and illustrated by scanning electron micrographs. © 1979 Plenum Publishing Corporation.