Foraging by fungus-growing termites (Isoptera: Termitidae, Macrotermitinae) in the Okavango Delta, Botswana

Abstract

Observations were made of foraging frequency and food selection by species of Macrotermitinae in a savanna habitat in the distal reaches of the Okavango Delta, Botswana. A removal experiment in the field was also conducted. Observable foraging showed seasonal peaks in frequency, related to temperature in Macrotermes michaelseni and to moisture in sympatric soil nesting Termitidae. Foraging was mostly on woody litter of the dominant canopy trees and mammalian dung. There was considerable overlap in the selection of food items between species but M. michaelseni were seen more frequently on items of woody litter greater than 6 mm in diameter. In Petri-dish trials Microtermes spp. workers were aggressive towards M. michaelseni individuals and in the field they foraged more frequently and effectively when M. michaelseni numbers were experimentally reduced. Macrotermes michaelseni appeared to avoid competition with other fungus-growing species by spatial separation within the habitat and some limited separation in food selection, but intense competition is probably rare as space and food resources may rarely be limiting.