ADAPTATIONS AND RESISTANCE OF ZOOPLANKTON TO STRESS - EFFECTS OF GENETIC, ENVIRONMENTAL, AND PHYSIOLOGICAL FACTORS

The ability of a species to adapt to stress factors such as exposure t o toxicants depends to a large extent on the presence of individuals t hat are able to respond to the exposure in a successful way. Several s trategies can be employed to cope with different stress factors. Inves tments on growth and reproduction, for instance, can be varied to meet the requirements of the environment. Large individuals generally have a high resistance against stress, but a large body size is often achi eved at the cost of other characteristics. In the present study, the r esistance of several clones of Daphnia to different stress factors, su ch as toxic cyanobacteria, a predator released chemical, and starvatio n, was investigated. The focus was on interactions among different fac tors and whether observed responses can be regarded as evolved adaptat ions for the different conditions. (C) 1998 Academic Press.