INTERCASTE, INTERCOLONY, AND TEMPORAL VARIATION IN CUTICULAR HYDROCARBONS OF COPTOTERMES-FORMOSANUS SHIRAKI (ISOPTERA, RHINOTERMITIDAE)

We characterized the variation in cuticular hydrocarbon mixtures betwe en seven colonies of the Formosan subterranean termite, Coptotermes fo rmosanus Shiraki, from the same population. We report differences betw een castes, between colonies, and within the population over time to a ssess seasonality. Colonies of C. formosanus from Oahu, Hawaii, were s ampled for 25 months. Each month, one sample each of 200 workers, 50 s oldiers, nymphs, or alates from each colony was subjected to gas chrom atography-mass spectrometry (GC-MS) analysis of the cuticular hydrocar bons. We resolved 39 individual peaks and identified 52 individual or isomeric mixtures of hydrocarbons. Only n-alkanes and methyl-branched alkanes occur; no olefins were found. Internally branched monomethylal kanes were the most abundant class of hydrocarbons, representing 45% t o 50% of the total. 9-;11-;13-Methylheptacosane accounted for over 30% of the total hydrocarbon for all castes. 2-Methyl- and 3-methylalkane s comprise approximately 30% of the total. Internally branched dimethy lalkanes constitute 15% to 20% of the total cuticular hydrocarbon. Onl y one trimethylalkane, 13,15,17-trimethylnonacosane, was found in smal l amounts. The hydrocarbon mixtures of all four castes were similar. Q uantitative differences in hydrocarbon mixtures among the castes were easily displayed using canonical discriminant analysis. Soldiers and w orkers are significantly different from one another and from nymphs an d alates. Nineteen peaks are statistically significant between workers and soldiers. Nymphs and alates were not statistically different. We detected statistically significant quantitative differences between co lonies in 18 peaks for workers and 12 peaks for soldiers. Each of the colonies of C. formosanus can be separated from the others by the prop ortions of their hydrocarbon components. We detected statistically sig nificant differences between months of the year for 12 peaks for worke rs and four peaks for soldiers; two peaks each for workers and soldier s showed distinct, seasonal trends. This seasonal shift in proportions of hydrocarbons correlates with the production of alates.