Huffaker's mite experiment
In 1958, Carl B. Huffaker, an ecologist and agricultural entomologist at the University of California, Berkeley, did a series of experiments with predatory and herbivorous mite species to investigate predator–prey population dynamics. In these experiments, he created model universes with arrays of rubber balls and oranges (food for the herbivorous mites) on trays and then introduced the predator and prey mite species in various permutations.
Source: Wikipedia — Huffaker's mite experiment (CC BY-SA 4.0)