Male-Produced Aggregation Pheromone of the Sloe Bug, Dolycoris baccarum L. (Hemiptera: Heteroptera: Pentatomidae)

The sloe bug, Dolycoris baccarum L. (Hemiptera: Heteroptera: Pentatomidae), is a Palearctic species and an important polyphagous pest. Previous studies have reported that male D. baccarum produce an aggregation pheromone, to which conspecific adults of both sexes respond. We used solid-phase microextraction (SPME) to collect volatiles released by sexually mature virgin males and females, and identified potential components of the male-produced aggregation pheromone. Analysis of the SPME samples by gas chromatography-mass spectrometry (GC-MS) revealed three male-specific components, alpha-bisabolol, trans-alpha-bergamotene, and beta-bisabolene, at a ratio of 100:10:3. A field trapping experiment showed that (+/-)-alpha-bisabolol alone attracted D. baccarum adults, and it was synergized by trans-alpha-bergamotene, but not (S)-beta-bisabolene. However, neither trans-alpha-bergamotene nor (S)-beta-bisabolene was attractive individually. A binary blend of (+/-)-alpha-bisabolol and trans-alpha-bergamotene in a 10:1 ratio was less attractive than caged live males, suggesting that further study is necessary to determine the absolute configuration or steroisomeric composition of the natural pheromone components. This is the first report of alpha-bisabolol and trans-alpha-bergamotene as semiochemicals among Pentatomidae, and the first to identify alpha-bisabolol from insects.