Tunnel formation by different numbers of eastern subterranean termites (Isoptera: Rhinotermitidae) in laboratory arenas

Eastern subterranean termite, Reticulitermesflavipes (Kollar), workers in six groups of 30 to 1000 were introduced into arenas containing moist builder's sand. In arenas containing low (30 to 125) termite numbers, 30 to 50% of the tunnel distance was constructed in 1d, significantly less than the 72 to 83% of the tunnel completion in arenas with higher (250 to 1000) termite numbers. At test completion (14 d), the tunnel distance of 84.73 +/- 7.86 to 140.02 +/- 8.43 cm in arenas with low (30 to 125) termite numbers was significantly less than the tunnel distance of 198.00 +/- 6.86 to 199.83 +/- 11.87 cm in arenas with high (500 and 1,000) termite numbers. Doubling termite numbers did not result in a doubling of termite tunnel distance. Regression analysis performed on tunnel distance recorded on days 1, 3, 7, and 14 for each termite number resulted in slopes that were significantly > 0 except for arenas with 250 termites. Results indicated that the lower termite numbers (30 to 250) continued to tunnel at a greater rate and longer time. The number of both primary and secondary tunnels at 14 d in arenas with 1000 termites (3.58 +/- 0.24 and 3.19 +/- 0.34, respectively) was significantly greater than in arenas with 30 termites (1.10 +/- 0.70 and 1.00 +/- 0.00, respectively). Overall, higher termite numbers within an arena increased in both number and diameter of primary and secondary tunnels. The tunnel network was constructed faster with high termite numbers (1000) and resulted in a 93% reduction in tunneling per termite compared with tunnel network construction at lower termite numbers (30). Higher termite numbers had higher survivorship but did not significantly affect the angle between the primary and secondary tunnel. Also, regardless of termite numbers fixed secondary tunnel angle efficiently divided the arena.