Mound dimensions, internal structure and potential colony size in the fungus growing termite Macrotermes michaelseni (Isoptera: Macrotermitinae)

External dimensions of mounds built by the fungus growing termite Macrotermes michaelseni (Sjostedt) were measured in periodically inundated grassland and flood plain woodland in the north of Botswana. Internal structure and dimensions of selected mounds were also assessed. Overall mound height differed within and between habitats and pediment width was greater in the grassland habitat but mean turret height did not differ significantly between habitats. Grassland mounds had broader but shallower fungus gardens and in all mounds a discrete nursery area was absent. These results are compared with similar data for M. michaelseni in Kenya. Reasons for the differences between the populations and their evolutionary consequences are discussed.