Present address: Frontier Research Center for Global Change, 3173–25, Showamachi, Kanagawaga, 236–0001, Japan.
Estimation of the longevity of C in terrestrial detrital food webs using radiocarbon (14C): how old are diets in termites?
Article first published online: 19 APR 2006
Volume 20, Issue 2, pages 385–393, April 2006
How to Cite
HYODO, F., TAYASU, I. and WADA, E. (2006), Estimation of the longevity of C in terrestrial detrital food webs using radiocarbon (14C): how old are diets in termites?. Functional Ecology, 20: 385–393. doi: 10.1111/j.1365-2435.2006.01081.x
- Issue published online: 19 APR 2006
- Article first published online: 19 APR 2006
- Received 15 June 2005; revised 9 September 2005; accepted 20 September 2005 Editor: S. L. Chown
- Diet age;
- food web;
- stable carbon and nitrogen isotope ratios;
- 1We propose that diets of consumers in a food web have various ages, where age is defined as the time elapsed since carbon (C) in the diet was fixed from atmospheric CO2 by primary producers. To examine the diet ages for primary consumers in a detrital food web, we measured the radiocarbon (14C) content of termites collected in Thailand in 1998 and 2004. Diet ages were estimated by comparing the 14C content of samples with records of atmospheric 14CO2, which doubled in the early 1960s as a result of nuclear weapons tests and decreased after the nuclear test ban treaty. For comparison, we measured the 14C content of bees as primary consumers in a grazing web at the same study site. Stable carbon and nitrogen (N) isotope ratios were also analysed.
- 2The 14C contents of the same species of termites decreased during the sampling interval, indicating that they used organic matter produced after the peak in atmospheric 14CO2. The diet ages were estimated to be 12–18, 7–13 and 5–9 years for the wood-feeder (Microcerotermes crassus), the soil-feeders (Dicuspiditermes makhamensis and Termes comis) and the fungus-grower (Macrotermes carbonarius), respectively. One colony of soil-feeder (T. comis), which nested in a fallen tree trunk, had exceptionally low 14C content, and its diet age was estimated to be around 50 years. The two bee species had lower 14C contents compared with the termites, and their diet ages were estimated to be 0 (Apis florea) and 2–4 years (Trigona sp.).
- 3Stable C and N isotope ratios of termites showed similar patterns as previously reported, and no clear difference was observed between 1998 and 2004. Although the bees and the fungus-growing termite had similar stable C and N isotope ratios, their diet ages differed.
- 4Our study suggests that radiocarbon can be used to estimate the diet ages of consumers in terrestrial food webs. Diet age should provide new insight into the trophic positions of organisms in grazing and detrital food webs and the interactions between these two webs.