Termite ecology in a dry evergreen forest in Thailand in terms of stable (delta C-13 and delta N-15) and radio (C-14, Cs-137 and Pb-210) isotopes

Stable (delta(13)C and delta(15)N) and radio- (C-14, Cs-137 and Pb-210) isotopes were determined for termites that have been sampled from a dry evergreen forest in Thailand. A wood-feeding termite, Microcerotermes crassus, was separated from soil-feeders: Termes propinquus, Termes comis and Dicuspiditermes makhamensis by delta(13)C and delta(15)N values. The Termes group in Thailand had less diverse values in delta(13)C and delta(15)N than those in Australia, where the feeding habits of the 'Termes' group are more diverse. Other soil-feeding termites produced similar delta(13)C values, but a larger range in delta(15)N values. C-14-percent modern carbon (pMC) values suggest that the soil-feeding termites used younger carbon than the wood-feeding termites, and this was consistent with the termites from Cameroon, central Africa. Values of delta(13)C and C-14-pMC indicate that surface soil was used by a soil-feeding termite, D. makhamensis, in making the nest mounds, and deeper soil (10-30 cm) by a fungus-growing termite, Macrotermes carbonarius Pb-210 and Cs-137 were scarcely incorporated into the termites, although Pb-214 was recovered from the workers. The results suggest that stable- and radioisotopes are useful in the study of detritivorous animals, organic matter decomposition and ecosystem engineering.