Sesquiterpenes pheromones

Sesquiterpene Pheromones from Flea Beetles—Practical Synthesis Based on Standard Methods... 

Almost simultaneously with the identification of 2E, 4 , 6Z- 10 COOMe, a thermally unstable stereoisomer, 2E, 4Z, 6Z- 10 COOMe 118, was found to be a key component of the male-produced sex pheromone of Thyanta pallidovirens> along with the sesquiterpenes (+)-a-curcumene, (-)-P-sesquiphellandrene, and (-)-zingiberene 119 [10,25]. 2E, 4Z, 6Z-10 COOMe was an essential component of the attractive blend, whereas any one, any two, or all three of the sesquiterpene components were equally effective as the other portion of the blend. None of the components were active alone. Pheromone blends attracted only females in both laboratory and field bioassays [10]. The same compounds are also produced by the congener T. custator [10] and other Thyanta spp. (J.G. Millar, unpublished data). 

The male produced sex pheromone of the red-shouldered stink bug, Thyantapallidovirens Stal (Hemiptera Pentatomidae), was shown to consist of a blend of methyl ( "2, Z 4,. Z6)-decatrienoate and the sesquiterpenes (+)-a-curcumene, (—)-zingiberene and (—)-P-sesquiphellandrene. In laboratory bioassays, sexually mature males attracted sexually mature females but not males, and females did not attract either sex. Pheromone... 

Queen pheromones ant alkaloids, lactones, pyrones, sesquiterpenes, pentadecene Cruz-Lopez etal. (2001)... 

Collection of volatiles from males feeding on pieces of cabbage revealed a blend of six male-specific sesquiterpenes, including hydrocarbons 24-28 and ketone 29, shown in Figure 19.5 (Bartelt et al., 2001). Compound 24 was the most abundant. One or more of these were thought likely to account for the pheromonal activity reported earlier. Hydrocarbon 28 [(+)-v-cadincnc is known from citronella oil (Herout and Sykora, 1958), but structures 24-27 and 29 were new. The opposite enantiomers of hydrocarbons 24 and 25 were previously isolated from the trees Nordmann fir (Abies nordmanniana) and silver fir (Abies alba) (Bartelt et al., 2001 Khan and Pentegova, 1988 Khan et al., 1989), and the opposite enantiomer of 27, known as ar-himachalene, is found in Himalayan cedar (Pandey and Dev, 1968). Neither compound 26 nor its enantiomer were known from nature, but... 

There are other examples of volatile hydrocarbon pheromones in beetles that have been researched less extensively. One of these is from the broad-homed flour beetle, Gnatocerus cornutus (F.) (Coleoptera Tenebrionidae), a common stored-product pest. Tebayashi et al. (1998) found that males produce at least one compound that was attractive to both sexes in laboratory bioassays and at sub-nanogram levels. The compound was identified as the sesquiterpene (+)-acoradiene. The beetle-derived enantiomer was subsequently synthesized... 

Muto, S., Bando, M. and Mori, K. (2004). Synthesis and stereochemistry of the four himachalene-type sesquiterpenes isolated from the flea beetle (Aphthona flava) as pheromone candidates. Eur. J. Org. Chem., 2004,1946-1952. 

Recently, germacrene-A (III) has been identified as the alarm pheromone of the sweet clover aphid Therioaphis trifolii (38). This alarm releaser, which has often been proposed as the progenitor of cyclic sesquiterpenes, constitutes the second compound with a germacrane-type skeleton to be identified as an insect pheromone. 

The scent scales on the wings of a male lycaenid, Lycaeides argyroqnomon, secrete a mixture of n-nonanal, hexadecyl acetate, and a sesquiterpene alcohol, tentatively identified as torreyol (5-cadinol) (XXVIII) (113) the absolute configuration of the sesquiterpene has not been determined. These male-derived pheromones appear to play an important role in the courtship behavior of this species. 

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