Cyclic CO₂ Release and Water Loss in the Western Drywood Termite (Isoptera: Kalotermitidae)

CO2 release and water loss patterns of Incisitermes minor (Hagen) pseudergates were investigated using flow-through respirometry techniques. Four hours of real-time CO2 release and water loss data were recorded for pseudergates of I. minor at 20–40°C. Cyclic release, but not traditional DGC, was the CO2 release pattern observed in these pseudergates. Variability of V˙co2 expressed as coefficient of variability (CV) was used to estimate the level of cycling in each recording. CV decreased exponentially with temperature. Mean V˙co2 values ranged from 0.24 ± 0.07 ml CO2 g−1 h−1 at 25°C to 0.89 ± 0.16 ml CO2 g−1 h−1 at 35°C. V˙co2 increased significantly (P = 0.014) with temperature, but was not influenced (P = 0.063) by body mass. Q10 for V˙co2 over the range of 20–40°C was 1.75 for I. minor pseudergates. Water loss cycled coincidently with CO2 release. Water loss rates ranged from 5.22 ± 1.97 mg H2O lost g−1 h−1 at 20°C to 17.96 ± 2.55 mg H2O lost g−1 h−1 at 40°C. Q10 for water loss over the range of 20–40°C was 1.86 for I. minor pseudergates. Daily respiratory water loss represented from 9.23% at 20°C to 4.72% at 25°C of total daily water loss. Cuticular water loss represented from 93.5% at 25°C to 89.1% at 30°C of total daily water loss.