Confirmation of soil‐feeding termites (Isoptera; Termitidae; Termitinae) in Australia using stable isotope ratios

Carbon (δ13C) and nitrogen (δ15N) stable isotope ratios of termites (Isoptera) were examined in Darwin, northern Australia. It is suggested that the stable isotope technique, together with phylogenetics, is a useful tool to understand the evolution of functional groups in detritivores. 2. A high δ15N value was observed in the Termes‐Capritermes branch of the subfamily Termitinae and the genus Amitermes, two distinct taxonomic groups that evolved from wood‐feeding to soil‐feeding in Australia. Among eight Termes‐Capritermes branch species, only two species (Xylochomitermes melvillensis and Ephelotermes melachoma) were discernible as wood/soil interface feeders, the remaining six species analysed were soil‐feeders, where the diet preference was identified by using δ15N of workers. 3. The Termes‐Capritermes group in Australia contains both wood/soil interface feeders and soil‐feeders, whereas wood/soil interface feeders in Cameroon are from the Termes‐Capritermes branch while soil‐feeders are from Cubitermes group. The result confirmed that soil‐feeding forms evolved both in Australia and Africa, but from different phylogenetic groups.