04031naa a2200169 a 450000100080000000500110000800800410001910000150006024501100007526000090018552032820019470000140347670000160349070000180350670000160352477303210354013150522008-10-06       2008    bl uuuu     u00u1 u    #d1 aTAYASU, I.  aFeeding group diversity of soil macrofauna (termites and earthworms) in the Lamto reserve in Ivory Coast.  c2008  aWe investigated carbon and nitrogen stable isotope ratios and radiocarbon concentration of soil macrofauna (termites and eathworms) obtained from the Lamto reserve in Ivory Coast. Two different vegetations were selected: a gallery forest along the Bandama river and a grass savanna dominated by Hyparrhenia and Andropogon. Three replicated plots were set in each vegetation. Termites and earthworms were sampled by hand-sorting. The isotope ratios of soils, leaf-litter and grass were determined and compared with the fauna. Noditermes aburiensis and Euchilotermes tensus, which are abundant soil-feeding termites in the gallery forest, had the highest values in both carbon and nitrogen isotope ratios within the gallery forest. Several species in the subfamily Termitinae and soldierless termites (the subfamily Apicotermitinae) had the ?elta-13C and ?elta-15N values lower than N. aburiensis and E. tensu. Cephalotermes rectangularis, Termes hospes and Amitermes evuncifer were plotted in the ?elta- 13C and ?elta-15N region, which is so-called a wood/soil interface feeder. Microcerotemes pauvus and other wood-feeding termites had the lowest ?elta-13C and ?elta-15N values. In contrast, Trinervitermes geminatus was the least enriched in nitrogen isotope ratio at the grass savanna. Epigeic species of Dichogaster had the lowest delta-15N and ?elta-13C values at both vegetation. Milsonia anomala, which is a common mesohumic endogeic earthworm in Lamto, had higher delta-15N values than epigeic species of Dichogaster. Delta-15N values in endogeic eudrilid worms were still higher, and they were the highest in the gallery forest. In total, categorization by the isotope ratios (Tayasu 1998) was in good agreement with the ecological categorization. Agastrodrilus opisthogynus, which has been sampled only in the grass savanna, had the highest delta-15N values in the grass savanna. Hyodo et al. (in press) have found that there is a good correlation between delta-15N and capital-delta-14C values. The fact suggests that termites and earthworms which consume more decomposed materials (?humification gradient? indicated by delta-15N; Tayasu et al. 1997) utilized ?aged? carbon indicated by capital-delta-14C. However, capital-delta-14C values in A. opisthogynus did not show the same trend, instead, the higher delta-15N values were considered to be caused by the trophic enrichment. Our results confirmed the hypothesis that Agastrodrilus opisthogynus is predatory (Lavelle, 1983). References: Lavelle, P. (1983) Agastrodrilus Omodeo and Vaillaud, a genus of carnivorous earthworms from the Ivory Coast. In: Earthworm Ecology (J.E. Satchell ed.) pp. 425-429. Chapman and Hall, London. Hyodo, F., Tayasu, I., Konaté, S., Tondoh, J.E., Lavelle, P. and Wada. E. (2008) Gradual enrichment of 15N with humification of diets in a belowground food web: relation between 15N and diet age determined using 14C. Functional Ecology in press Tayasu I. (1998) The use of carbon and nitrogen isotope ratios in termite research. Ecological Research 13: 377-387. Tayasu,I., Abe,T., Eggleton,P. and Bignell,D.E. (1997) Nitrogen and carbon isotope ratios in termites: an indicator of trophic habit along the gradient from wood-feeding to soil-feeding. Ecological Entomology 22: 343-351.1 aHYODO, F.1 aKONATÉ, S.1 aTONDOH, J. E.1 aLAVELLE, P.  tIn: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.