A great diversity of defensive chemicals has been described in termite soldiers equipped with a unique defensive organ, the frontal gland. Along with the functional diversity of these compounds, reflecting the evolutionary history of particular lineages and their defensive strategies, a considerable degree of chemical variability often occurs among species and populations. Thus, the chemistry of termite defense may provide information on the phylogeny and geographic dispersal of species and populations. In this paper, we report on the anatomy of the frontal gland and on the diversity of soldier defensive chemicals in the sand termite, Psammotermes hybostoma, from nine colonies and five different localities in Egypt. Using gas chromatography-mass spectrometry, a total of 30 sesquiterpene hydrocarbons, or their oxygenated derivatives, were detected, and the chemical identity of most of them identified. In addition, a ketone, an ester, and a diterpene were identified in some colonies. Within colonies, the chemical composition was stable and did not differ among soldier size categories. However, there were pronounced quantitative and qualitative differences in frontal gland chemicals among colonies and geographic locations. The findings are discussed in a broader comparison with other termite taxa.

Institute of Organic Chemistry and Biochemistry Evolutionary Biology and Ecology Université Libre de Bruxelles

Institute of Organic Chemistry and Biochemistry Faculty of Science Charles University Prague

Institute of Organic Chemistry and Biochemistry Flemingovo n 2 166 10 Prague Czech Republic

Institute of Organic Chemistry and Biochemistry Laboratoire Ecologie et Evolution CNRS UMR 7625 Université Pierre et Marie Curie

Institute of Organic Chemistry and Biochemistry Prague Czech Republic

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