The topological fortress of termites

Termites are known for building some of the most elaborate architectures observed in the animal world. We here analyse some topological properties of three dimensional networks of galleries built by termites of the genus Cubitermes. These networks are extremely sparse, in spite of the fact that there is no building cost associated with higher connectivity. In addition, more "central" vertices (in term of betweenness or degree) are preferentially localised at spatial positions far from the external nest walls (more than in a null network model calibrated to exactly the same spatial arrangement of vertices). We argue that both sparseness and the particular spatial location of "central" vertices may be adaptive, because they provide an ecological advantage for nest defence against the attacks from other insects. © 2008 Springer Berlin Heidelberg.