The chemistry of the defensive secretions of South American termites

Walmsley, Sandra (1980) The chemistry of the defensive secretions of South American termites. University of Southampton, Doctoral Thesis.

Abstract

The chemical constituents of the defence secretion produced by the soldier caste of forty species of South American termites were investigated with the major emphasis being placed on the volatile components of the secretion. Six species of the genus syntermes were studied and it was found that cis-8ocimene constituted 90% of the secretion of S.'dirus;'S. peruahus, S. molestus, S. brevimalatus and Syntermes sp. In contrast none of this compound is produced by S. randis and it was shown that these differences in the secretion can be related to the defensive behaviour of these species. The analysis of the soldier secretion of Curvitennes strictinasus showed the presence of limonene, terpinolene, p-cymen-8-ol, tridecan-Z-one, a tridecen-2-one, trans,trans-farnesal and cis,trans-farnesal. The major component being TFFpieoTene -which -accounts Tor 60% of the secretion. The soldiers of Cortaritermes silvestri were found to produce three monoterpene hydrocarbons and cis-pin-3-en-2-yl acetate. The synthesis of this acetate from a-pinene by reaction with lead tetraacetate was carried out. Three of the four diterpenes in this secretion were identified as the triacetate, diacetate, propionate and acetate dipropionate of 3a,98,12a-trihydroxy11(12),15(17)-trinervitadiene, the former two compounds have not been identified previously. The soldier secretion of Nasutitermes sp. n. D., Nasutitermes kemneri and Constrictotermes cyphergaster were und to contain a mixture of monoterpene hydrocarbons and diterpenes. The major diterpene in the soldiers of Nasutitennes sp. n. D. being 98-hydroxy-1(15),8(19)-trinervitadiene and the ma or iterpenes in N. kemneri are 2a,38-dihydroxy-1(15),8(9)- and 1(15), 8(19)-trinervitadienes. Analysis of an extract of the soldier caste of Amitermes sp. X. indicated the presence of eight sesquiterpene hydrocarbons,-1T-epoxy-cis-eudesmane, eudesm-l1-en-48-ol and another eudesmane alcohol, the synthesis of 5-e~~ pi-eudesm-ll-en-4a-ol from (-)-carvone via a Robinson ring annulation is discribed. Preliminary gas chromatography mass spectroscopy was carried out on extracts of the soldiers of the genera Procornitermes, Cornitennes, Rhinotennes, Amitermes, Armiterries, Triangularitermes and Hotunditerines which revealed a range of compounds from methyl esters, to methyl Ketones, alkanes and alkenes. The latter two genera were found to produce diterpenes. A total of fifteen species of termites from the genera Angularitennes, Diversitermes, Velocitermes and Nasutitermes were found to have soldiers which produced secretions containing mixtures of mono- and diterpenes.

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