Survival and Growth of the Stygophilic Amphipod Gammarus troglophilus Under Laboratory Conditions

Abstract

Abstract Amphipods play important roles in the cycling of nutrients and energy in many aquatic systems where they display a wide range of feeding modes ranging from detritivore to predator. Although the biology of many amphipod species has been examined, little is known of hypogean amphipods inhabiting cave streams. Gammarus troglophilus is a stygophilic amphipod that co-occurs with the federally endangered stygobiont G. acherondytes in cave streams of the Salem Plateau Karst Region of southwestern Illinois. With the goal to establish a self-sustaining laboratory population of cave amphipods to obtain amphipods for lethality experiments, we tested hypotheses relating the survival and growth rates of G. troglophilus collected from cave streams to different laboratory conditions of food and water velocity. We used a series of microcosm experiments to test the hypotheses that survival and growth are not affected by type of water (cave water vs. amended water), water velocity (static vs. dynamic/recirculating...