Modelling of Termite Nest formation

Key words: Social insects, termites, fractal growing model.

In collaboration with Michel Lepage, Pascal Jouquet ( Laboratoire Fonctionnement et Evolution des Systèmes Ecologiques, UMR 7525- Ecole Normale Supérieure) and Yves Le Goff (Ecole Nationale Supérieure des Arts et Métiers, Laboratoire Mécanique des Fluides).

The aim of this collaboration with biologists is to understand the mechanisms of nest construction for a particular specie of termites (macrotermes bellicosus). These termites are living in africa (in dry as well as forest areas), they build specific structures, rather irregular, but with some charateristic towers-like components.

Their nest is composed of several internal and external structures, with food strorage area, mushrom plantation (they actually grow and eat a particular specie of mushroom), queen chamber and nursery. The nest is a structure that evolves gradually, with respect to the size and age of the colony, as well with respect to the environment and climatic conditions. The challenge is to understand the connections between nest architechture and climatic conditions (and eventually elaborate behavioural models of it).

In this work, we consider a simplified model of some external nest structure, that are usually built by the colony within a single night. The proposed model is based on a population behaviour with elementar social interactions (an ACO model), that has been derived from biologic observations. 2D simulation proves the capability of such a model to produce fractal structures, similar to the natural ones.

A fractal model of small towers construction.