1Université de Bourgogne, UMR CNRS 5548, Développement, Communication Chimique, 6 Bd Gabriel, 21000 Dijon, France.
2INRA, Laboratoire de recherches sur le arômes, 21034 Dijon, France.
3INRA, Laboratoire de Phytopharmacie, Route de Saint Cyr, 78026 Versailles Cedex, France.
Despite the biological and economic significance of trail-following pheromones in termites, very few were chemically identified. In Macrotermes annandalei, one of the most abundant termite present in Northern Vietnam, trail-following bioassays showed that the sternal gland is the only source of the pheromone. 5,000 sternal glands of large workers were extracted in hexane. Extracts were purified by silica gel column chromatography and fractionated by capillary-GC. The biologically active fraction, analyzed by GC-MS, revealed a single major compound. Its complete chemical structure was determined as(Z)-3-dodecen-1-ol (DE-OH). Biossays showed unequivocally that DE-OH is the major component of the trail-following pheromone of M. annandalei. Synthetic DE-OH induced recruitment andorientation activity as the glandular extracts. DE-OH activity scale ranged from 10-3 ng to 10 ng/cm. Maximun activity occured at 10-1 ng/cm. Quantification of DE-OH in extracts (about 1ng/sternal gland) wasalso consistent with experimental estimations from activity tests. Interspecific choice bioassays have revealed the existence of a commoncompound eliciting trail-following in several Macrotermitinae from Asia (M. barneyi, O. hainanensis, O. maesodensis) and Africa (M. bellicosus, M. subhyalinus). This compound was demonstrated to be DE-OH by bioassays and GC-MSanalysis. In addition to this major compound, there are evidences for amulti-component system inducing trail specificity.