Soil-particle selection by the mound-building termite Macrotermes bellicosus on a sandy loam soil catena in a Nigerian tropical savanna uri icon

abstract

  • A field study was conducted in an inland valley in Bida, Nigeria, during the dry season (February 2005) to investigate the effects of toposequence on soil-particle selection by Macrotermes bellicosus, a dominant species in Nigerian tropical savanna. The principal mound structures were compared with natural horizons of surrounding pedons (smallest volume of a representative soil for description and sampling) on a sandy loam catena by measuring particle size distribution with five sand and two silt fractions. Soil samples were collected from identifiable biogenic structures i.e. external wall, internal wall, hives, royal cell, base-plate and pillars, in mounds and soils below the nest, and from natural horizons of pedons 2 m away from the mounds. Soil morphological alterations by the termites were not visible in the pedons. Particle size distribution varied widely among structural units of the mounds. In particular, structural units in the nest body (i.e. hives, royal cells and base plates) contained finer particles than the other mound constituents (i.e. walls and pillars) and soils below the mound, except for the fringe mound, where nest body and other mound constituents had similar particle size distribution. The combination of silt and sand distribution differentiates nest bodies from the other mound structures at any location on the toposequence. In spite of considerable variability in the mounds, the mound structures, particularly the upland mounds, apparently had finer particles than the upper horizons of the adjacent pedons. It was recorded that M. bellicosus generally selected the same particle size whatever the local soil along the toposequence, but clay content in the subsoil and accessibility to clay-rich soil horizons may define nest-building capacity

publication date

  • 2009
  • 2009
  • 2009