Termite Foraging and Preference to Soil Type and Moisture Content in Laboratory Bioassays

Subterranean termites, Coptotermes acinaciformis, were tested for their preference to different soil types in a laboratory condition at different soil moisture levels. The soil types provided were topsoil, fine sand, potting mix and peat at moisture levels of 0, 5, 10, 15 and 20% for 30 days. The experimental apparatus involved individual termites foraging from nesting jars connected to four sets of standing perspex tubes filled with the four soil types attached to the jar lid on top at each moisture level. Foraging activities were observed at 12 hr intervals to avoid disturbance while the number of days taken by termites to penetrate and forage inside each soil column was analyzed as a measure of preference by termites. The results showed that soil type had a significant effect on termite preference whereas soil moisture content did not have any significant effect. At lower moisture levels of 0 and 5%, termites preferred fine sand. Topsoil was preferred at moisture levels of 10, 15 and 20%. Termites built distinct tunnels and tunneling branches in Fine sand, most of the time starting from top to bottom, and covered them with dark clay particles brought from the nesting jars. However, they transported soil particles from Topsoil columns to the nesting jars to build foraging layers on top. The average rate of soil transport from a topsoil column was higher at higher moisture levels.