Many cockroach species court each other before mating. Often, the female begins courtship by releasing pheromones that attract males. She may also do a "calling" display, dropping her tail and exposing her abdomen. A male called in by a female touches antennae with her, which in some species starts an elaborate interaction. For example, Honduran cockroaches (Latiblattella sp.) circle around each other, head to tail, pressing together. Turning his tail end to the female, the male lifts his wings to expose glands on his abdomen that release male pheromones. Straddling the male, the female licks his abdomen, moving up towards his head until their tail ends connect. In other species, courtship is minimal, with the male just backing his tail end into the female for copulation, which may take an hour or more. Once fertilized, females typically make egg cases (ootheca), and either brood internally or deposit them in a warm, humid place for hatching.

Insects are by far the most diverse and abundant group of organisms on Earth. More than one million insect species have been identified, and estimates of how many species exist range into the tens of millions. Insects got their start way back, in the Paleozoic (about 500 million years ago) and have evolved in tandem with flowers (coevolution). Insects have become specialized on particular flowers, leading to complex sets of adaptations that couple them in a feeding and pollination relationship (a mutualism). Specialization allows for many types of insects to live in the same habitat, accommodating their exceptional biodiversity. In a backyard in the temperate zone, one might find several thousand species of insects. Specialization can occur within one plant species as well, with different insects using different parts of the plant. In just one species of tropical tree, Dr. Terry Erwin of Smithsonian's National Museum of Natural History found about a thousand species of beetles.