Respiration of opistophthalmus pugnax (thorell) (scorpionidae) after treadmill exercise and book lung occlusion
Van Aardt, W.J.
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After the four spiracle pairs of Opistophthalmus pugnax were stepwise occluded, the oxygen consumption rate (MO2) and the accumulation of d-lactate in the haemolymph were measured. D-lactate and MO2 was also measured during a 15-minute treadmill exercise at a run speed of 0.025 m/sec. The highest d-lactate concentration of 15 mmol/l was obtained after a 15-minute exercise followed by 11 mmol/l d-lactate when all eight spiracles were closed off for one hour. The MO2 value of 1.93 mmol/l obtained from four closed spiracles does not differ significantly (P<0.05, t-test) compared with the MO2 value of eight open spiracles. Possible mechanisms of metabolic rate depression and metabolic down-regulation are discussed. Low haemolymphpH (7.38±0.08) in O. latimanus and other scorpions compared with other terrestrial arthropods are a hallmark inherent to scorpions living in dry xeric conditions