Odonata
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Odonata is the order that includes dragonflies and damselflies. Both adults and nymphs in the order are predaceous, feeding on mosquitoes, midges, and other pests. Individuals will try to bite when handled, but only very large individuals will be able to inflict pain. They do not sting.
Identification
Adults are generally large insects, 1-3.5 in. in length and are often brightly colored. The wings are long, membranous, and veined. The compound eyes are large, often taking up much of the head. The antennae are short and bristle-like. The prothorax is small, the thorax mostly composed of the second two segments. The tarsi have three segments. Male copulatory organs are found on the ventral side of the 2nd abdominal segment. Cerci are present and have 1 segment. In males, they are modified into claspers for mating. The mouth parts are for chewing.
Life Cycle
Dragonflies undergo simple metamorphosis. Nymphs are aquatic and carnivorous, feeding on other insects and sometimes even small fish. They capture their prey with modified labium, which are generally folded under the head. When in use, the labium are thrown out quickly to catch the prey in claw-like structures at its apex. This modified structure can reach up to a 1/3 of the nymph's body length. Mating will often occur during flight, with the male holding the female's head or prothorax with his claspers, both male and female flying in tandem. Eggs are laid on vegetation near the pond or stream, or on the water's surface.
Habitat
Nymphs are aquatic, and are generally found in freshwater ponds and streams. Adults are usually found in the vicinity of nymph habitats. However, they are very strong fliers and can range over several miles.
Taxonomy
Number of species
There are 400 species found in North America, and 4950 worldwide.
Suborders
There are two suborders in this order, principally separated by wing venation. Other defining characteristics include wing shape, position of wings at rest, and appendages on the abdomen.
- Anisoptera (Dragonflies)
- Zygoptera (Damselflies)
Bibliography
Borrer, DJ and RE White. A Field Guide to Insects: America north of Mexico. Houghton Mifflin Company: Boston, 1970. ISBN 0-395-91170-2