The concentration variability of Ca, Mg, Na, K ions in the haemolymph and urine has been analyzed in Procambarus clarkii during interecdysis instar, the animals having been kept under several temperature conditions (10, 15, 20, 25, 30 degrees C) during two different periods of time (48 h and 7 days). The environmental temperature did not affect the concentration of sodium and calcium in the haemolymph. Nevertheless the above parameter had an effect on the concentration of potassium and magnesium in the haemolymph as well as on the concentration of the four cations considered in the urine of Procambarus clarkii. No significant differences have been found in relation to the time of exposure.
