Dragonflies are big insects, reaching about 4 inches in body length. These large insects help in the control of several agricultural plagues, such as ants and caterpillars. As active hunters, dragonflies can catch small butterflies and moths, flies and other insects while flying. They also feed on the larvae of these agricultural plagues.
Midges and mosquitoes are an important part of the adult dragonfly diet. While in their larval stage, dragonflies can eat the larvae of mosquitoes, midges and other biting insects, often smaller than themselves. The adult dragonfly can eat many mosquitoes and midges in a day, but they also feed on the larvae of these biting insects. Dragonflies do not have a stinger and use their legs to catch their prey while flying.
Dragonflies play an important role in the food chain. As well as feeding on smaller insects, they are prey to bigger invertebrates, such as some species of spider, and many vertebrates, such as wagtails, hobbies and other birds and frogs. While living in the water during their larval stage, they are part of the diet of fish, frogs, newts and other aquatic animals.
Dragonflies found in Texas come in a variety of metallic colors, including blue, yellow, purple, pink, red and green. Males are often more colorful than females, and some have wings with elaborate patterns. The blue dasher (Pachydiplax longipennis) male, which is common in Texas, shows a metallic blue body and head, with delicate transparent wings. As the larvae of dragonflies are sensitive to water pollution, the presence of these insects is also an indication of water purity.