A b s t r a c t. Nests habour ants and termites and protect them from harsh environmental conditions. The structural stabilities of nests were studied to ascertain their relative vulnerability to environmental stresses. Arboreal-ant nests were pried from different trees, while epigeous-termite nests were excavated from soil surface within the sample area. Soils without any visible sign of ant or termite activity were also sampled 6 m away from the nests as control. Laboratory analysis result showed that irrespective of the tree hosts, the aggregate stabilities of the ant nests were lower than those of the ground termite, with nests formed on Cola nitida significantly showing lower aggregate stability (19.7%) than other antnest structures. Clay dispersion ratio, moisture content, water stable aggregate class <0.25 mm and sand mass were each negatively correlated with aggregate stability, while water stable aggregate class1.00-0.50 mm gave a positive correlation. Nest structures were dominated more by water stable aggregate class >2.00 mm but path analysis demonstrated that water stable aggregate class <0.25 mm contributed most to the higher aggregate stability of the termite nest than the other nest. Nest aggregates had greater structural stability compared to the control soil. The higher structural stability of termite nests over other nest and soil was considered a better adaptive mechanism against body desiccation.K e y w o r d: structural stability, arboreal-ant nests, derived savanna, termite nests
INTRODUCTIONWithin the tropics, the most abundant animals are the ants which belong to the order Hymenoptera in the family Formicidae, and the termite in the order Isoptera in the family Termitidae (Jouquet et al., 2002). Related findings for instance from Ghana and Nigeria showed that as many as 80% of the total number of individual insects found on cocoa are ants (Hölldobler and Wilson, 1990). This in addition to the original lifestyle as predators makes them major components of both the terrestrial and arboreal ecosystems.These soil macro-invertebrates (ants and termites) are regarded as ecosystem engineers (Jouquet et al., 2006). Termites are divided into either wood-dwelling or soil dwelling, but majority of the tropical termites are the soil dwellers that construct either above ground nests or dig underground galleries and are found mostly on dry areas. Wood dwelling termites do not create nests, but live in excavated galleries in the dry woods. Ants are responsible mainly for arboreal nests. They live mainly on live trees where they build nests with litter materials, soils and some decomposed organic materials on top of trees. The scholars stated that nests formed by the black ants, popularly known as carton nest, are formed by ants chewing up pieces of wood and mixing them with honeydew and a type of syrup very similar to those of wasps. Ants and termites are very vulnerable insects and require the protection of their bodies and colonies by improving the structural stability of their nests.Ants and termite...