Weird Diets and Niches! Aaron starts off with the Epomis beetles, a group of carabid beetles that have evolved to feed on frogs many times their size. learn about how these grubs manage to subdue their amphibian prey, and the unique environmental conditions that lead to its evolution. Rustin follows with the various species of cleaner wrasse fish. Learn about the good (cleaning mutualists), the bad (the occasional mucus-snacking wrasse), and the ugly (the cleaner wrasse mimics).