Termite ecology in a dry evergreen forest in Thailand in terms of stable ( <b>δ</b> ¹³ C and <b>δ</b> ¹⁵ N) and radio ( ¹⁴ C, ¹³⁷ Cs and ²¹⁰ Pb) isotopes

Abstract

Stable (δ 13 C and δ 15 N) and radio‐ ( 14 C, 137 Cs and 210 Pb) 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 δ 13 C and δ 15 N values. The Termes group in Thailand had less diverse values in δ 13 C and δ 15 N than those in Australia, where the feeding habits of the ‘ Termes ’ group are more diverse. Other soil‐feeding termites produced similar δ 13 C values, but a larger range in δ 15 N values. 14 C‐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 δ 13 C and 14 C‐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 . 210 Pb and 137 Cs were scarcely incorporated into the termites, although 214 Pb 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.