Termites and methane

Rasmussen and Khalil measured laboratory methane emission rates of one species of termite, extrapolated this to a global methane production estimate and concluded that the estimate made by Zimmerman et al. was inflated. The authors obtained 15 specimens of Zootermopsis angusticolis (Hagen) from Ras-mussen and Khalil and repeated their experiment using wood as a substrate and a 3-h enclosure time. The emission rate at 20 degree C was about 2.4 mu g per termite per day (2.7 times higher than they reported). The experiment was repeated at 25 degree C after the termites had been conditioned at the new temperature for 24 h. The new emission rate was 5.7 mu g per termite per day (more than 6 times higher than they reported). When the termites were put in our flow-through system (3 ml min super(-1)) their emission rates were 3.5 and 6.0 mu g per termite per day at 20 and 25 degree C respectively. The emission rate of a similar species (Zootermopsis nevadensis (Hagen)) was 7.8 mu g per termite per day at 20 degree C in our flow-through system.