Respiratory gas exchanges of termites from the Sabah (Borneo) assemblage

Abstract

Abstract.Oxygen uptake and carbon dioxide release at 28°C were determined in worker castes of twenty‐six species of forest termites from the Danum Valley Conservation Area, south‐east Sabah, by Warburg manometry.Metabolic rate varied inversely with body weight in a suite of soil‐, wood/soil‐ and wood‐feeding species, giving a slope (in a log–log plot) of – 0.63. However, a number of large species, actively foraging forms such as Macrotermes malaccensis, M. gilvus, Havilanditermes atripennis and Hospitalitermes hospitalis, but also the wood‐feeding Schedorhinotermes sarawakensis, showed an oxygen consumption greater than expected for their body weight. Rates of methane emission were above 0.100 μmol g–1 h–1 in seventeen species, with very high fluxes in two wood/soil‐feeders, Termes borneensis (0.546 ± 0.163 μmol g–1 h–1) and Prohamitermes mirabilis (0.303 ± 0.123 μmol g–1 h–1). Of the fifteen remaining species, seven were soil‐feeders, five were wood‐feeders, two were wood/litter‐feeders and a single species fed on lichen and moss. Low or negligible CH4 emissions (< 0.100 μmol g–1 h–1) were observed in three other species, all wood‐feeders.An apparent respiratory quotient (RQapp) was calculated using xCO2 and xO2 (corrected for methane emission, but not hydrogen). Mean RQapp was at or above 1.00 in eleven species and between 0.95 and 1.00 in a further six species, the two sets of species together representing all trophic groups, including lichen‐feeders. This is argued to be consistent with carbohydrate being the principal substrate supporting respiration.