Chemotaxis of the Pinewood Nematode, Bursaphelenchus xylophilus, to Volatiles Associated with Host Pine, Pinus massoniana, and its Vector Monochamus alternatus
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The pinewood nematode (PWN), Bursaphelenchus xylophilus, the most important invasive species in pine forests of Asia, is transported to new pine hosts by beetles of the genus Monochamus. Third-stage dispersal juveniles (JIII) aggregate in pupal chambers around the vector as it matures. We demonstrated that the ratio of three terpenes (α-pinene, β-pinene, and longifolene at 1:2.7:1.1) released by larval Monochamus alternatus strongly attract JIII, whereas the different ratio (1:0.1:0.01) of these three terpenes found in healthy xylem of Pinus massoniana attracts only the propagative stage (Jn) of the nematode. We suggest that the volatiles produced by the host plants could be the basis of a chemoecological relationship between plant parasitic nematodes and their vector insects. Capture of JIII with terpene-baited trap tubes deployed for 2 hr in the field was demonstrated. This technique may lead to the development of rapid sampling methodologies for use at either ports-of-entry or in the field.
KeywordsAggregation Bursaphelenchus xylophilus Chemo-sensation Location Monochamus alternatus Terpenes
We thank Daniel Miller, David Kulhavy, Marc Linit, and two anonymous reviewers for critical comments on the manuscript, and Prof. Xingzhong Liu for his technical assistance. We are especially grateful to Leland Humble for his review and editing of the revised manuscript. This study was funded by the CAS Knowledge Innovation Program (KSCX2-YW-N-006), National Natural Science Foundation of China (30621003, 30525009) and a grant (Chinese IPM0502) from the State Key Laboratory of Integrated Management of Pest Insects and Rodents, IOZ. The publication of this work is also supported by the EU ALARM project. All experiments described in this paper were done according to the rules of the ethical board for animal experiments complying with the current laws of China.
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