Medusae were
placed in 1 mm-filtered Ohio River water in a large
aquarium, and they were randomly selected for the
three experiments, which were conducted at room temperature (20–228C). For the first two experiments,
the three potential prey Daphnia magna Mu¨ller 1785,
Daphnia lumholtzi Sars 1885 and Bosmina longirostris were
obtained from stock cultures originally collected in the
Ohio River and maintained at the University of Louisville