Behavioral responses to heat in artificial galleries by the western drywood termite (Isoptera: Kalotermitidae)

摘要

We quantified the response of the western drywood termite, Incisitermes minor (Hagen), to heat within two galleries routed into a wood cross. Nymphs were placed in the gallery of the right arm and after 2 h, the gallery temperature was raised >40 deg C. Trials also were conducted with the addition of alates or soldiers to groups of nymphs. Termites moved only as far as necessary to avoid temperatures >40 deg C and never relocated to areas furthest from the highest gallery temperatures. Termites tended to occupy the central, cross-shaped portion of the gallery. Mean temperature preference values for nymphs only, nymphs with alates, and nymphs with soldiers were 29.5 deg, 31.9 deg, and 28.9 deg C, respectively, indicating that the presence of other castes had no effect on termite thermal preference. The corresponding mean highest gallery temperatures were 42.8 deg, 44.2 deg, and 42.8 deg C and the mean lowest temperatures were 25.8 deg C. The presence of alates or soldiers had no effect on the distribution of termites. A calculated mean termite walking speed of 1.41 cm/s suggests that I. minor can respond and move quickly away from increasing gallery temperatures. Trials also were conducted with the termites introduced into the left arm of the cross. Results of choice tests conducted with termites permitted to move either upward or downward in the vertical gallery, or right or left in horizontal galleries, indicate a possible turn bias in I. minor.