Physiological Adaptations in Crustacea To the Environment: Oxygen Consumption as a Function of Body Weight and Environmental Temperature in the Terrestrial Isopod, Porcellio Laevis Latreille (Isopoda, Oniscoidea)

Abstract

[Oxygen consumption in intermoult tenth instar Porcellio laevis increased significantly (P<0.01) with decreasing body weight. The largest individuals (96-104 mg) had a mean oxygen consumption of only 106 μl O2/g wet weight/hr compared to the smallest isopod (43-52 mg) which had a mean oxygen consumption of 325 μl O2/g wet weight/hr. No significant variation was observed between males and females. The unit rate of metabolism for the isopod was calculated to be 180 μl O2/g wet weight/hr at 20° C. There was little variation in oxygen uptake over a temperature range of 5° C to 15° C, while the lowest and the highest oxygen uptake were observed at 5° C and 25° C, respectively. An increase in temperature beyond 30° C resulted in a significant decrease (P<0.01) in respiratory activity. Isopods respiring at 25° C in the dark showed significantly higher (P<0.01) oxygen consumption rate (180 μl O2/g wet weight/hr) than did those tested under daylight illumination (130 μl O2/g wet weight/hr). Porcellio adults have been found to be conformers since they reduce their oxygen consumption rate when the level of oxygen in the atmosphere of their niche is reduced., Oxygen consumption in intermoult tenth instar Porcellio laevis increased significantly (P<0.01) with decreasing body weight. The largest individuals (96-104 mg) had a mean oxygen consumption of only 106 μl O2/g wet weight/hr compared to the smallest isopod (43-52 mg) which had a mean oxygen consumption of 325 μl O2/g wet weight/hr. No significant variation was observed between males and females. The unit rate of metabolism for the isopod was calculated to be 180 μl O2/g wet weight/hr at 20° C. There was little variation in oxygen uptake over a temperature range of 5° C to 15° C, while the lowest and the highest oxygen uptake were observed at 5° C and 25° C, respectively. An increase in temperature beyond 30° C resulted in a significant decrease (P<0.01) in respiratory activity. Isopods respiring at 25° C in the dark showed significantly higher (P<0.01) oxygen consumption rate (180 μl O2/g wet weight/hr) than did those tested under daylight illumination (130 μl O2/g wet weight/hr). Porcellio adults have been found to be conformers since they reduce their oxygen consumption rate when the level of oxygen in the atmosphere of their niche is reduced.]