Olfactory Reception of Conspecific Aggregation Pheromone and Host Volatile Terpenes by Asian Larch Bark Beetle, Ips subelongatus

Terpenes volatiles from the stem barks and needles of Dahurian larch (Larix gmelinii), Prince Rupprecht larch (Larix principis-rupprechtii), and Korean larch (Larix olgensis), which are common hosts in the range of Ips subelongatus in northeastern China, were entrapped by dynamic headspace collection technique, and then the hexane elution of the volatiles was analyzed by chiral gas chromatography (GC) and GC-mass spectrometry (MS) in order to identify components of the volatiles. Totally 12 monoterpenes was identified, which are mainly consists of S-(-)- alpha -pinene, R-(+)- alpha -pinene, 3-carene, R-(+)- beta -pinene, and S-(-)- beta -pinene accounting for more than 80% of the total collected monoterpenes. Furthermore, the olfactory sensitivity and selectivity of I. subelongatus to synthetic host volatiles were assayed by a coupled gas chromatograph-electroantennographic detector (GC-EAD) and electroantennogram (EAG). The olfactory responsiveness to S-(-)- alpha -pinene, 3-carene, (+)-limonene, - gamma -te