Termites nest inside the cockroach family tree
About 4,600 cockroach species fill Blattodea, yet only some thirty haunt human buildings. Roachoids appear by the Carboniferous around 320 million years ago; modern forms date to the Late Jurassic. Genetics place termites deep within cockroaches, not beside them.
English turned the Spanish cucaracha into cock and roach by the 1620s, and the scientific name comes from Latin blatta, a light-shunning insect, a word Romans also used for mantids. Termites were long treated as their own order, Isoptera. A 1934 hypothesis linked them to wood-eating Cryptocercus roaches because both harbour the same gut flagellates, and genetics now confirms that termites evolved from true cockroaches, so many authors rank them as an epifamily inside Blattodea.
Most species are about thumbnail size. The Australian giant burrowing cockroach reaches 8 centimetres and 35 grams, Megaloblatta longipennis stretches to 97 millimetres, and the smallest, living among leaf-cutter ants, are about 3.5 millimetres. The body is broad and flat, with a waxed exoskeleton stiffened by calcium carbonate, tough forewings shielding the flying hind pair, and spiny legs whose grip on awkward surfaces has inspired robot designs.
Habitats range from leaf litter, rotting wood and forest canopy to deserts and water. Aquatic species snorkel with the tip of the abdomen or carry an air bubble under the thoracic shield, staying under for up to 40 minutes. Australia has about 450 species, North America 50, and only about four widespread ones are regarded as serious pests. The Asian cockroach, unusually, flies toward bright surfaces.
Many species gather using pheromones, some released in droppings with help from gut microbes. German cockroaches lay scented fecal trails that lead others to food, water and shelter. Experiments with scented robots showed roaches weigh just darkness and crowd size, accepting even a well-lit hideout once enough others choose it; individuals raised alone explore and eat less.
Source: Cockroach
