Two-year old incipient colonies of the Formosan subterranean termite (C. formosanus) and Asian subterranean termite (C. gestroi) were placed in artificial trees (20 x 15 cm and 20 high) filled with segments (ca. 5 x 10 cm and 10 – 20 cm long) of wet Spruce and connected at the bottom to planar arenas (1 x 1 m) filled with moisten sand to compare their tunnel geometries propagated from trees. The results showed that there was no significant difference in the number of primary or secondary tunnels propagated from trees between them, but C. formosanus constructed significantly shorter primary tunnels and longer secondar tunnels than C. gestroi. Tunnels width of primary and secondary tunnels of C. formosanus were significantly wider than those of C. gestroi. The length ratio between primary and secondary tunnels was larger for C. gestroi than C. formosanus, and C. formosanus branched more frequently than C. gestroi. The results suggested that C. formosanus tunnels were configured for “searching area effect,” strategy whereas those of C. gestroi were configured for “searching distance effect” strategy.
