Distribution, Density and Evolution of Macrotermes bellicosus Nests (Isoptera: Macrotermitinae) in the North-East of Ivory Coast

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Abstract
The abundance and distribution of M. bellicosus mounds were studied in 5 habitats of the Sudanian zone, Ivory Coast, ranging from scrub savanna to dry deciduous forest. The densities ranged from 2.2-37.5 ha-1 (live nests), and from 1.0-20.2 ha-1 (dead nests). Nest distribution appeared random or slightly overdispersed. A sampling area on a lateritic plateau was surveyed in Dec. 1979 and again in Nov. 1981. In 1979, from measurements on 52 live mounds, significant relationships were drawn between mound volume, height and basal area. The density of live mounds dropped drastically on the lateritic plateau within 2 yr (1979-1981), from 14.3 down to 0.8 ha-1. A regression curve was computed between initial mound volume and soil lost by erosion. Some possible reasons for the observed high mortality are discussed, particularly the role of predators, the aardvark and doryline ants. The unusual high mortality brought to the ecosystem 0.75-1 mm ha-1 yr-1 of eroded soil, about 35 kg (d.w.) [dry weight] of fungus combs and at least 25 kg (w.w.) [wet weight] of termite tissue.