Stone Pine Volatiles and Host Selection by Tomicus destruens (Wollaston) (Coleoptera: Curculionidae, Scolytidae) Voláteis de Pinheiro-Manso e Sele o do Hospedeiro pela Hilésina Tomicus destruens (Wollaston) (Coleoptera: Curculionidae, Scolytidae)

Mature adults of the pine shoot beetle Tomicus destruens reproduce in trunks of dying Mediterranean pines. However, there is no information about chemical stimuli governing host selection by T. destruens. The aims of this study were: 1) to identify volatiles released by the bark of stone pines (Pinus pinea) behaviorally and electro-physiologically active on T. destruens; 2) to verify which blends and concentrations of such volatiles act differently on males and females. A four-arm olfactometer was used to test behavior of walking adults of T. destruens in relation to various sources of volatiles, including bark, its collected volatiles and a synthetic blend. For each odor, the behavior of both males and females was recorded individually. Bark extracts were then analyzed by coupled gas chromatography and mass spectrometry (GC-MS) and tested by gas-chromatography coupled with electro-antennography (GC-EAD) on male and female antennae of T. destruens. In addition, a blend of synthetic compounds chosen from among those inducing EAD responseswas tested in the olfactometer at five concentrations. Behavior and EAD responses were not affected by sex, with males and females showing similar results. Five compounds extracted from bark were active on T. destruens antennae: limonene, β-caryophyllene, α-pinene, β-myrcene, and α-terpinolene. Among extracted volatiles, limonene and β-caryophyllene were known to be repellent to T. destruens, whereas attraction to a synthetic blend of α-pinene, β-myrcene and α-terpinolene was positively correlated with concentration, although a repellent effect was noted at the highest concentrations. Os adultos da hilésina Tomicus destruens reproduzem-se em troncos de várias espécies de pinheiros da regi o mediterranica. No entanto, n o se conhecem os estímulos químicos que condicionam a respetiva sele o dos hospedeiros. Os objetivos do presente estudo s o: 1) identificar os voláteis da casca do pinheiro-manso (Pinus pinea) que influenciam a resposta eletrofisiológica e comportamental de T. destruens e 2) determinar quais as misturas e concentra es de odores que afetam diferencialmente os dois sexos. A atratividade dos adultos da hilésina em rela o aos voláteis (incluindo casca, voláteis da casca e uma mistura sintética) foi estudada usando um olfatómetro de quatro bra os. Para cada odor o comportamento de machos e fêmeas foi estudado individualmente. Amostras de casca foram analisadas através de cromatografia gasosa e espectrometria de massa (GC-MS), tendo sido testados em machos e fêmeas de T. destruens através de cromatografia gas