Thysanura (=Zygentoma) - The Bristletails, Silverfish and Firebrats
Thysanurans, or three-pronged bristletails, are the order believed to be the link between ancient wingless insects and the more evolved winged insects. Thysanurans probably resemble the first insects that ever existed and specimens have been found preserved in rocks dating back to the Carboniferous period (345 million years ago). They are small insects measuring up to 50mm (less than 2”), most of that length its “tail”. In fact, the ordinal name Thysanura is derived from the Greek words "thysano-", (fringed) and "ura" (tail). In addition to having an abdomen ending in three “tails” (which are actually two cerci and a telson), they also have long filiform antennae. There are two families of Thysanurans: the Lepismatidae and the Nicoletiidae. The Nicoletiidae are tiny (7-18mm), have no eyes and can only be found within the nests of ants and termites. The Lepismatidae have small compound eyes and, in some species, the bodies are covered in scales. Fragile insects, they spend most of their life concealed beneath or within houses, ground litter, stones, logs, bark, soil, and almost any dark place where food can be found. Commonly referred to as silverfish (AKA fishmoths), they are fast-running insects that emerge after dark to search for food. They survive on a wide range of nourishment, including fungal hyphae (mycelium), algae, lichens, fallen fruit and starchy vegetable matter. A few species are resistant to desiccation and are well adapted to survive in man-made environments. Some pest species, called firebrats, are found in areas of intense heat (like bakeries and kitchens), while other species of Thysanurans are able to survive in deserts. There are about 700 known species.