Canadian Forest Service Publications
Steps in the biosynthesis of fuscumol in the longhorn beetles Tetropium fuscum (F.) and Tetropium cinnamopterum Kirby. 2013. Mayo, P.D.; Silk, P.J.; Cusson, M.; Béliveau, C. Journal of Chemical Ecology 39:377–389.
Available from: Atlantic Forestry Centre
Catalog ID: 34762
CFS Availability: PDF (request by e-mail)
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Fuscumol ((2S,5E)-6,10-dimethyl-5,9-undecadien-2-ol) was recently identified as the male-produced aggregation pheromone of the brown spruce longhorn beetle, Tetropium fuscum (F.), and the eastern larch borer, Tetropium cinnamopterum Kirby. Several other species use this homoterpenoid alcohol motif, its ketone, or its acetate as part of their pheromone system. Investigation of the biosynthesis of this compound in these two Tetropium species demonstrated that geranylacetone ((5E)-6,10-dimethyl-5,9-undecadien-2-one) and farnesol ((2E,6E)-3,7,11-trimethyl-2,6,10-dodecatrien-1-ol) are both intermediates in this process. This was accomplished by applying deuterium-labeled geranylacetone and deuterium-labeled farnesol in separate experiments to the abdominal sterna of live T. fuscum and T. cinnamopterum and analyzing the deuterium labeling in the fuscumol and geranylacetone emitted by the insects with solid-phase microextraction (SPME) and GC/MS analysis. Deuterium labeling studies also showed that nerolidol ((3S,6E)-3-hydroxy-3,7,11-trimethyl-1,6,10-dodecatriene) and 2,3-epoxyfarnesol are not intermediates in fuscumol or geranylacetone synthesis in T. fuscum or T. cinnamopterum. Tissue-specific expression of T. fuscum farnesyl diphosphate synthase (TfFPPS), an enzyme expected to provide a key fuscumol precursor, was measured. TfFPPS transcripts were relatively abundant in male midguts, but were also present at significant levels in other tissues.
Plain Language Summary
Male and female beetles use pheromones to find each other for mating on a suitable host tree. In the case of Tetropium fuscum (Brown spruce longhorn beetle, BSLB), a European invasive insect now in Nova Scotia damaging red spruce, it is the male that produces the pheromone, fuscumol, aggregating both sexes on the tree. Our results show that this insect makes the pheromone in its own biosynthetic process in the mid-gut and not deriving it from food ingredients. This knowledge contributes to our understanding of the communication processes of these beetles, their taxonomy and also may help develop new control processes to ultimately slow their spread.