Termite soil preferences and particle selections: strategies related to ecological requirements

Summary.

At the Lamto Savanna Ecological Station (Côte d'Ivoire), Odontotermes nr. pauperans (Termitidae, Macrotermitinae) was observed to build mounds enriched with fine particles. Using laboratory experiments we studied the selection of building materials by worker termites offered soil from two contrasting horizons: superficial soil (15-20 cm) and a deeper layer (70-80cm). The physical and chemical properties of the unused soil and subsequent termite constructions (foraging galleries and fungus-comb chambers) were compared in each case.¶When presented with a single soil type, the termites modified soil texture for different parts of their structure. Termite building activity increased when presented with both soil types and a notable selection was observed in the use of a given soil type for a specific part of the structure built.¶We conclude that termites utilise soil particles selectively, favouring finer particles and making constructions which match ecological, physiological, and behavioural needs. Compared with material from deeper horizons, less energy was expended when surface soil was used as a resource for gallery building and less C and N supplementation was needed. In contrast, termites preferred deeper soil for constructing fungus-comb chamber walls because this material has greater water-holding capacity.