Scolytidae compounds

Figure 6.9 Examples of pheromone components of bark beetles (Scolytidae) and ambrosia beetles (Scolytidae and Platypodidae) classified by likely biosynthetic origin (based on Francke and Schulz, 1999). (A) References for identification and/or behavioral activity of isoprenoid pheromone compounds are as follows-. 2-methyl-3-buten-2-ol (Bakke efa/., 1977 Giesen etal., 1984 Klimetzek etal., 1989a Lanne etal., 1989), 3-methyl-3-buten-1-ol (Stoakley etal., 1978 Bowers and Borden, 1990 Bowers etal, 1991 Zhang efa/., 2000), 3-methyl-1-butanol (Renw ick etal, 1977), 3-hydroxy-3-methylbutan-2-one (Francke and Heeman, 1974 Francke etal 1974), ipsenol and ipsdienol...

Figure 6.11 Biosyntheses of isoprenoid pheromone components by bark and ambrosia beetles from host conifer monoterpenes. (A) Conversion by the male California fivespined ips, Ips paraconfusus Lanier (Coleoptera Scolytidae), of myrcene from the xylem and phloem oleoresin of ponderosa pine, Pinus ponderosa Laws., to (4S)-(+)-ipsdienol and (4S)-(-)-ipsenol, components of the aggregation pheromone (Hendry et al., 1980). (B) Conversion by male and female I. paraconfusus of (1 S,5S)-(-)-a-pinene (2,6,6-trimethyl-bicyclo[3.1,1]hept-2-ene) from the xylem and phloem oleoresin of P. ponderosa to (1 S,2S,5S)-(+)-c/s-verbenol (c/s-4,6,6-trimethyl-bicyclo[3.1,1]hept-3-en-2-ol), an aggregation pheromone synergist and of (1 R,5R)-(+)-a-pinene to (1 fl,2S,5fl)-(+)-frans-verbenol (frans-4,6,6-trimethyl-bicyclo[3.1,1]hept-3-en-2-ol), a compound of unknown behavioral activity for /. paraconfusus. Male and female western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera Scolytidae), convert (1 S,5S)-(-)-a-pinene to (1S,2ft,5S)-(-)-frans-verbenol, an aggregation pheromone interruptant and (1R,5R)-(+)-a-pinene to (1 R,2S,5R)-(+)-frans-verbenol, a compound of...

Figure 6.14 Examples of the application of normal-phase, radio-HPLC to the analysis of de novo biosynthetic pathways in bark beetles (Scolytidae). Derivatization of 14C-labeled ipsenol from Ips paraconfusus (A, B) and 14C-labeled ipsdienol from Ips pini (C, D) leads to expected retention time shifts of radioactivity for each compound and derivative. Derivatization of /. paraconfusus ipsenol with (2/= )-(+)-a-methoxy-a-(trifluoromethyl) phenylacetic acid (MTPA) leads to the formation of only one diastereomer [(4S)-(-)-ipsenoyl-(2 P )-2 -methoxy-2 -phenyl-2 - (trifluoromethyl) phenylacetate] indicating the de novo biosynthesis of highly pure (4S)-(-)-ipsenol (B) Derivatization of I. pini ipsdienol with (1 S)-(-)-camphanic acid leads to the formation of both diastereomers [(4R)- -)- and (4S)-(+)-ipsdienyl-(TS)-camphanates] indicating the de novo biosynthesis of approximately 90 percent-(4/ )-(-)-ipsdienol (D). Figures adapted from Seybold et al. (1995b).

Wood D. L., Stark R.W., Silverstein R. M. and Rodin J. O. (1967) Unique synergistic effects produced by the principal sex attractant compounds of Ips confusus (LeConte) (Coleoptera Scolytidae). Nature 215, 206. 

A second example is the spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera Scolytidae), a major cause of mortality in mature spruce stands. Gries et al. (1992) found that the terpene verbenene (31 in Figure 19.5), was emitted from the beetles, predominantly from females, and concluded that it is a pheromone component. The oxygenated compounds seudenol, frontalin, and l-methyl-cyclohex-2-en-l-ol, were previously identified as pheromone components in this species. Attraction to verbenene alone was demonstrated in field traps, and it enhanced captures to the other pheromone components. The absolute configuration of verbenene has not been investigated. 

Bark beetles are of great economic importance, which is one of the reasons more research has been done on the pheromones of the Scolytidae than on those of any other family of Coleoptera. Their pheromone systems also seem to be typical of the Coleoptera in that while there is considerable diversity in pheromone structure within this family, there also seems to be a pattern of structures, particularly within a genus. The first pheromone identified from a coleopterous species was from Ips paraconfusus Lanier (then I. confusus) by Silverstein et al. (13). Three compounds — ipsenol (I), ipsdienol (II), and cis-verbenol (III)... 

Relatively few pheromones have been identified from species in this family. The first curcullonld pheromone Identified, that of the boll weevil, Anthonomus qrandls Boheman, is terpenoid in character like those of the Scolytidae. Two terpene alcohols (IX, X) and two aldehydes (xi, XII) were Isolated and identified from male weevils and from frass (21). All four of these compounds are required to elicit optimum attraction. 

GREGOIRE, J.C., BAISIER, M DRUMONT, A., DAHLSTEN, D.L., MEYER, H., FRANCKE, W., Volatile compounds in the larval ffass of Dendroctonus valens and Dendroctonus micans (Coleoptera, Scolytidae) in relation to oviposition by the predator, Rhizophagus grandis (Coleoptera, Rhizophagidae). J. Chem. EcoL, 1991, 17, 2003-2019. 

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