If one turns a stone over in a river or stream, it swarms with tiny animals: caddisflies, water beetles, freshwater shrimp, and snails. The invertebrates living on the beds of water bodies that can be seen with the naked eye, called macroinvertebrates, are rather unimposing, but for science and the protection of surface waters they are of great importance.

The western corn rootworm, one of the world's most damaging maize pests, can use plant defense compounds to defend itself against its own natural enemies, so-called entomopathogenic nematodes.