Dragonflies and Damselflies

   The gaudy quick-darting Odonata have always intrigued man. Dragonflies are shown on ancient pottery of the Americas, on Ori­ental scrolls, paintings, embroidered silk, and fine china, and in relief on precious metals. In literature their shimmering presences are often evoked by poets and novelists. The order derives its name from the Greek word odontognata, meaning "toothed mandibles." This is an apt description, for the approximately 5,000 Odonata species include some of the fiercest arthropod carnivores. Yet they are not best known for their predatory habits; dragonflies and damselflies, as the Odonata are commonly called, attract immediate attention because of their large brilliantly colored bodies and spectacular flying abilities. They are considered to be the best fliers in the insect world.

   Unlike their two primitive relatives, they have been well studied since they were first classified by the eighteenth-century zoologist Linnaeus. Fossil specimens of the ancestors of today's Odonata have been found from as far back as the Carboniferous period. Those huge predecessors had wingspans measuring up to 30 inches and were probably the size of an average modern bat. By the Jurassic period, some 180 million years ago, dragon­flies had evolved to pretty much their present-day size and structure.

   Like the Ephemeroptera and the Plecoptera, the Odonata are considered amphibiotic. They live in water as larvae and near water as adults. Odonata, found throughout the world, are divided into two main sub-orders—the Anisoptera (dragonflies) and the Zygoptera (damselflies). These are quite similar but have different nymph-stage characteristics and adult structures. Also, dragonfly and damselfly wings differ markedly.