PHYSIOLOGICAL AND BEHAVIORAL ADAPTATIONS OF AN EPIGEAN AND A HYPOGEANDWELLING POPULATION OF ASELLUS-AQUATICUS (L) (CRUSTACEA, ISOPODA)

An epigean living population of A. aquaticus was compared with an unpi gmented and eyeless subterranean dwelling population of the same speci es. The latter was found in a karstic system in south-east Romania. Th e oxygen consumption of individuals of both populations was investigat ed with a closed respirometer. Movement and feeding activities were st udied in infrared light using a video camera technique. Compared to th e hypogean population, the epigean one feeds actively, its movement is limited, it has a low respiration rate, and the individual oxygen con sumption is higher. The differences in the respiration, movement and f eeding patterns are discussed using field and laboratory data. We conc lude that the two different populations of A. aquaticus showed special adaptations to the habitats within which they were found. With furthe r morphological and genetic investigations this subterranean populatio n of A. aquaticus could be described as a new taxon.