The dynamics of body water in the booklouse Liposcelis bostrychophilus (Badonnel)

Liposcelis bostrychophilus , whether in culture or fasting, was found to maintain the amount of its body water at nearly 66% of its fresh weight while in air of at least 60% relative humidity between temperatures of 7°C and 42°C. In these conditions intervals of body water loss reaching 1 to 2 μg alternated with recovery of the loss by the physiological absorption of water from vapor at a rate many times that of the water loss. In other conditions a loss of one‐half of the body water could be survived. The time dependence of a change in the mass or the tritium content of body water was that of a single compartment from which water molecules were cleared by first‐order processes, primarily diffusion, having rates in proportion to the momentary mass of body water while water entered from vapor, was metabolically produced, and some evidently was cleared by processes having rates independent of the body water mass. The physiological absorption process was seen to reach its full rate or to stop within minutes, and it was accompanied by a reduced rate of body water clearance. In any particular physical surroundings the body water mass approached a steady‐state value with the half‐time of the first‐order clearance processes. A few measurements of these quantities, over the ranges of temperature and relative humidity, afforded accurate prediction of the recovery time or the longevity in other conditions.