A quantitative study of seasonal foraging by the grass harvesting termite, Trinervitermes geminatus (Wasmann), (Isoptera, Nasutitermitinae) in Southern Guinea savanna, Mokwa, Nigeria

Abstract

Trinervitermes geminatus (Wasmann) harvests standing grass tussocks which are cut into pieces and carried back to the nest. During this activity a certain proportion is left on the soil surface as litter whilst some is ingested. Foraging is mainly accomplished during the dry season (mid-October to the end of April) for periods of 2-4 h daily, either early in the morning, in the evening, or occasionally during both morning and evening. The duration and daily pattern of foraging is partly dependent on temperature, with a lower temperature threshold of 20° C and an upper threshold of 35° C below or above which foraging is restricted.The quantity of grass cut down and carried back to the nest by a population of 737 m^-2 (3.08 g m^-2) was estimated at 60.3 kg ha^-1a^-1 with approximately 18 kg ha^-1a^-1 cut and left as litter. Estimated consumption whilst foraging was approximately 20.4 kg ha^-1a^-1, giving a total consumption of about 81 kg ha^-1a^-1. Compared with a total estimated grass production of 3157 kg ha^-1a^-1 and consumption by cattle of 1404 kg ha^-1a^-1, the quantity of grass removed by T. geminatus, amounting to only 3.1% of the net primary production, did not appear to be economically significant in this locality.