Zoraptera is a small order of insects that is poorly known and understood. The name zoraptera means ‘true wingless’ so they were named before the winged forms were discovered. The delightful common name is angel insect. There is only a single family in the order and 26 described species. These colorless little insects are about 3 mm in length. They have beadlike antennae and simple chewing mouthparts. Their bodies are typical of insects: head, three-part thorax with six jointed legs and a segmented abdomen with short cerci at the end. Their legs are adapted for walking and most are wingless but some have two paired membranous wings with reduced venation. Winged forms have eyes while the flightless forms are usually blind. The wings are used for dispersal and then dropped.
Zoraptera have a simple hemimetabolous life cycle. The females lay eggs which hatch into nymphs that develop into adults without a pupation stage. They are similar in appearance and development to booklice (Order Psocoptera) and may be related to them. However there are few examples of Zoraptera in the fossil record so we really don’t know their origins. Good specimens do exist in Cretaceous amber but these are modern looking. Genetic studies may eventually answer the question of their origins.
Zorapterans live in small, loose colonies of about 10-100 members. These colonies are usually under bark or rotting logs but have also been found in man-made sawdust piles. They do not like light and seldom come to the surface in daytime so are probably more common than they seem. They feed on fungi, both hyphae and spores and are also predatory, consuming mites and nematodes. There are two types of individuals in the colonies. Most are blind and wingless and do the work of the colony. Some are eyed and develop wings and these disperse to form new colonies. Their dispersal capabilities must be adequate as at least one species occurs on the Hawaiian Islands. It is possible that because the insects are so small and light, a group of alates were blown high in the atmosphere and then carried to the Islands.
Most zorapterans are found in the tropics but a few species live in temperate zones in the Northern Hemisphere. The northernmost individuals are usually found in human sawdust piles. This is one of the smallest orders of insects and has no economic importance to man so is relatively unstudied.
For more information: http://tolweb.org/Zoraptera http://www.cals.ncsu.edu/course/ent425/compendium/zorapt.html
