Experimental manipulation of termites (Isoptera,Macrotermitinae) foraging patterns in a Sahelo-Sudanese savanna: effect of litter quality

Summary The foraging pattern of four sympatric fungus-growing termite species was followed for five months of the dry season in a semi-arid savanna (Senegal). Experimental plots were established with and without termites (exclusion with insecticide) and amended with different litter quality: Acacia leaves, millet canes, ground millet (<500 µm), Combretum wood and cattle manure. Results showed different foraging patterns between the fungus-growing species. Odontotermes nilensis, for example, rapidly developed its foraging activity on the litter. In contrast, Macrotermes subhyalinus delayed its foraging activity but, extensively collected the food after its discovery. Differences in food preference were evident between the termite species: Odonto-termes nilensis foraged preferentially on millet, canes and Acacia leaves, Macrotermes subhyalinus preferred cane and ground millet. Ancistrotermes guineensis selected the millet, and Microtermes sp. was mostly recorded foraging on pieces of dead wood. Relationships between different foraging parameters were established to assess the relative intensity of this activity over the dry season. The comparison between untreated plots and plots treated with Fipronil® (Aventis) clearly demonstrated that the exclusion of termites from part of the savanna is possible and that this possibility can be used to study their role on the soil and organic matter cycle in situ.