Gnathotrichus sulcatus

Borden J. H., Chong L., McLean J. A., Slessor K. N. and Mori K. (1976) Gnathotrichus sulcatus synergistic response to enantiomers of the aggregation pheromone sulcatol. Science 192, 894—896. 

Byrne K. J., Swigar A. A., Silverstein R. M., Borden J. H. and Stokkink E. (1974) Sulcatol population aggregation pheromone in the scolytid beetle, Gnathotrichus sulcatus. J. Insect Physiol. 20, 1895-1900. 

A population aggregation pheromone has been identified from males of the scolytid, Gnathotrichus sulcatus (69). A 65/35 mixture of the (S)-(+) and the (R)-(-) enantiomers of 6-methyl-5-hepten-2-ol (sulcatol) was isolated from the boring dust and shown to attract both females and males in a ratio of 2.65 1, respectively. 

In 1974, Silverstein and coworkers isolated and identified sulcatol (103, Figure 4.51) as the male-produced aggregation pheromone of Gnathotrichus sulcatus, an economically important ambrosia beetle in the Pacific coast of North America. They showed the natural pheromone to be a 35 65 mixture of (R)-103 and (5)-103 by -NMR analysis of its Mosher ester (a-methoxy-a-trifhioromethylphenylacetate). The reason why the beetle produces a mixture of enantiomers was unclear at the time of its discovery. 

Both the enantiomers of sulcatol [21], the pheromone of the ambrosia beetle Gnathotrichus sulcatus, were totally inactive. Their mixture, however, showed strong pheromone activity. 

Borden, J.H., L. Chong, J.A. McLean, K.N. Slessor, and K. Mori Gnathotrichus sulcatus S)oiergistic Response to Enantiomers of the Aggregation Pheromone Sulca-tol. Science 192, 894-896 (1976). 

It seems as though insect communication systems have exploited chirality in every way possible. We have already seen the simplest case where one enantiomer, (+ )-brevicomin, is attractive to the western pine beetle and the other enantiomer, (—)-brevicomin, is not. It has also been observed that males of the scratch-faced ambrosia beetle Gnathotrichus sulcatus of the Pacific coast of North America produce both enantiomers of the aggregation pheromone sulcatol drawn in Figure 4.8 [17]. It... 

Byrne, K. W., A. Swigar, R. M. Silverstein, J. H. Borden, and E. Stokkink, Sulcatol Population aggregation pheromone in Gnathotrichus sulcatus, J. Insect Physiol. 20 1895-1900 (1974). 

Sulcatol (229), the sex pheromone of Gnathotrichus sulcatus, has been synthesized in its optically active (S)-(+)- and )-forms from... 

Gnathotrichus sulcatus produces 6-methyl-5-hepten-2-ol (sulcatol) (229) as its aggregating pheromone, as a 65 35 mixture of 5-(+) and R- —) enantiomers (31S). Borden et al. (316) found that this ambrosia beetle responded maximally to a racemic mixture (50 50) of the two enantiomers. In fact, the response to the racemic mixture was significantly greater than it was to a 65 35 ratio. More recent work, however, suggests that G. sulcatus responds to some extent to 5-(+)-sulcatol alone, that it does not respond to the 5 -(—)-isomer, and that the range of active ratios is much wider than previously indicated (317). In addition, Borden and coworkers (317) have found that G. retusus responds to (5)-(+)-sulcatol in an upwind laboratory bioassay and that the response appears to be inhibited to some extent by the S-(—)-enantiomer. They speculate that speciation may depend in part on the enantiomeric compositions of the pheromone. 

This report also presents a detailed decision analysis for the manufacture of gossyplure, the pheromone of the pink bollworm. The material was to be used in permeation schemes to disrupt mating of the pink bollworm in the cotton fields of the Southwest. The conclusion was that such a venture appears modestly attractive . Although some of the assumptions were based on solid research results, many of them were necessarily somewhat arbitrary. Note that the report is already dated by recent progress. For example, mass trapping of the ambrosia beetle Gnathotrichus sulcatus is now on a commercial basis (see below). 

Mori, K. Synthesis of optically active forms of sulcatol, the aggregation pheromone in the Scolytid beetle Gnathotrichus sulcatus. Tetrahedron 31, 3011—3012 (1975). 

McLean, J. A., and J. H. Borden Survey for Gnathotrichus sulcatus (Coleoptera Scolytidae) in a commercial sawmill with the pheromone, sulcatol. Canadian J. Forest Research 5, 586—591 (1975). 

Suppression of Gnathotrichus sulcatus with sulcatol-baited traps in a sawmill... 

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