VENTILATORY AND LOCOMOTORY ACT IN ANOXIA AND SUBSEQUENT RECOVERY OF EPIGEAN AND HYPOGEAN CRUSTACEANS

Locomotory and ventilatory responses to severe hypoxia and subsequent recovery were investigated in 3 amphipod crustaceans: 2 hypogean speci es (1 interstitial species Niphargus rhenorhodanensis and 1 Karstic sp ecies N. virei) and 1 epigean species (Gammarus fossarum), and in an e pigean population of 1 isopod crustacean (Asellus aquaticus). These sp ecies displayed respectively 46.7h, 52.1 h, 6.3 h and 19.7 h lethal ti mes for 50% of the population (LT(50)) values for anoxic survival. The aim of this study was to determine why the hypogean species displayed a survival time during than that of Gammarus, Asellus and most other epigean crustaceans, and to better understand the ecological problems concerning Niphargus survival and perennation modalities in subterrane an habitats which very often present hypoxic conditions during a hydro logical cycle. The high resistance to severe hypoxia of hypogean anima ls partly results from an adaptation to the limitation of energetic ex penditure linked to locomotion and ventilation in anaerobiosis, and fr om a decrease of general metabolism in severe hypoxia.