Estimation of food composition of Hodotermes mossambicus (Isoptera: Hodotermitidae) based on observations and stable carbon isotope ratios

The diet of the harvester termite Hodotermes mossambicus was investigated at two sites with distinct dietary components: C(4) grasses (delta 13C isotope values, -13.8 parts per thousand to -14.0 parts per thousand) and C(3) plants (delta 13C isotope values, -25.6 parts per thousand to -27.1 parts per thousand). By comparing observations of food items carried into the colony by the termites and carbon isotope ratios of whole termites (that determined assimilated carbon), the relative proportion of the C(3) and C(4) plant food components of the termite diet was estimated. There was agreement between the observational data and stable carbon isotopic data, with grass representing approximately 93% of the diet of H. mossambicus at two study sites (urban and rural) on the South African highveld. However, when correcting for mass of food items, that is, C(3) and C(4), carried by termites, the proportion of grass (C(4)) in the diet may be underestimated.