Abstract: Identification of aggregation pheromone released by Frankliniella intonsa males play a key role in bio-control of this pest. Except for the western flower thrips Frankliniella occidentalis, little is understood on aggregation pheromones in other thrips species. In the laboratory we tested the behavioral responses of adult F. intonsa and F. occidentalis to odor sources emitted from their corresponding adult males with Y-tube olfactometer. Head-space volatiles released by adult males of F. intonsa were collected using solid-phase microextraction (SPME) and identified by gas chromatography-mass spectrometry (GC-MS) with different GC columns (BGB-176 SE and CP-chirasil-Dex CB). Behavioral results showed that both male and female F. intonsa were attracted to the odors released by conspecific males. GC-MS analysis showed that two major components in head-space volatiles were released by F. intonsa, i.e., (R)-lavandulyl acetate and neryl (S)-2-methylbutanoate, which are the same compounds that are reported in volatiles from F. occidentalis males. However, quantitative analysis showed that the ratios of (R)-lavandulyl acetate to neryl(S)-2-methylbutanoate released by F. intonsa and F. occidentalis adults differed. Behavioral experiments further showed that the difference in the ratio of the two components plays an important role in interspecies identification between F. intonsa and F. occidentalis. The results suggest that different species of thrips of the same genus Frankliniella may share the same aggregation pheromones.

Key words: Frankliniella intonsa, aggregation pheromone, (R)-lavandulyl acetate, neryl (S)-2-methylbutanoate, olfactory response, odor sources, volatiles