Abstract
Oxygen consumption relative to oxygen tensions ranging from 20.7 to 383.1 mm Hg was determined for 3 nematodes of diverse habit. Rhabditis elegans. a free-living nematode, showed a linear increase of consumption with tension until a critical tension of 121.5 mm Hg was reached. Beyond this point further increases had little effect upon consumption. R. strongyloides. a nematode recovered from skin lesions on a cow, reached a critical tension at 58.5 mm Hg. Small horse strongyle larvae, free-living stages of a parasitic form, consumed oxygen at a very low and almost constant level over the entire range of oxygen tensions used. Survival times of Rhabditella axei and Rhabditis strongyloides were found to be directly related to oxygen tension. The adaptive significance of these findings is discussed.