Termitarium volume as a determinant of invasion by obligatory termitophiles and inquilines in the nests of Constrictotermes cyphergaster (Termitidae, Nasutitermitinae).
A range of organisms can be found inside termite nests where the degree of association can vary from facultative to obligatory dependence. Studies of the dynamics of nest invasion are still unresolved, so how and when cohabitants enter termite nests remain open questions. This study analyzed one specific aspect of the dynamics of termite nest invasion by obligatory termitophiles and inquilines, i.e., whether cohabitants were more likely to invade a nest when it reached a critical nest size. We collected 36 Constrictotermes cyphergaster nests of different sizes and sampled their cohabitant fauna. Our results indicated that the invasion of C. cyphergaster nests by obligatory termitophiles and inquilines was dependent on nest size. There appeared to be a critical nest size above which nests were more prone to invasion. Above this size, there was a significantly higher likelihood of finding obligatory cohabitants. Termitophile species were observed in nests ≥2.2 L, whereas inquiline species were only occur in nests ≥13.6 L. This may indicate that the obligatory cohabitants studied here did not occupy C. cyphergaster nests at random and that they were dependent on features that made these nests suitable for cohabitation, which are linked to colony development.