Experimental studies on the respiratory rates of mites (Acari) from beech-woodland leaf litter.

Respiratory rates (oxygen consumption) of thirty-six species of mites from beech-woodland leaf-litter were measured at 10°C in a Cartesian Diver. The first published information on the respiratory rates of Prostigmata, and new information on the respiratory rates of adult and juvenile stages of Mesostigmata and Cryptostigmata are presented.The most important single variable influencing respiratory rate (for mites of a given size at a constant temperature) was activity; however, progressively increasing levels of activity increased not only the level of metabolism, but also the slopes of the regression lines of log10 respiratory rate against log10 weight, from a minimum of 0.54 in very inactive Cryptostigmata to a maximum of 1.03 in extremely active Prostigmata. The effect of activity on the metabolic cost of searching for prey in predatory mites is discussed.Respiratory rates per unit weight declined smoothly as a simple function of weight throughout the life-histories of two species of mite, but not in two others. Sexual differences and differences in the respiratory rates of gravid and nongravid females of several species were also demonstrated.Results are compared with previously published work on mite respiration. Some discrepancies are apparent between our data and that of other workers. Possible reasons for, and consequences of these discrepancies are discussed.