Dragonflies and Damselflies: Odonata

Odonates (OH-duh-nayts) have large eyes with ten thousand to thirty thousand individual lenses in each eye. The eyes of dragonflies meet, or almost meet, on the top of the head, while those of damselflies are widely separated, giving them a "barbell" look when viewed head on. The adults have four wings. The wingspans range from 0.8 to 6.5 inches (20.3 to 165 millimeters). Dragonfly wings are very strong and provide these insects with amazing flight maneuverability. The spiny legs are well developed for perching and seizing prey, animals that are hunted for food, but are of little or no use for walking. Instead, dragonflies rely on their four powerful wings for getting around. The large, strong wings are mostly transparent, see-through, and are supported by a network of veins. Some species have distinctly colored or patterned wings.

The ten-segmented abdomen of the dragonfly is long and slender. Males have a unique reproductive system with a special second set of structures on the underside, at the base of the abdomen. Damselfly and some dragonfly females have well-developed egg-laying structures for inserting their eggs into plant tissue. In most other dragonflies this structure is not very well developed, and their eggs are simply dropped into water. Both sexes have appendages (uh-PEN-dih-jehz), fingerlike structures, on the tips of their abdomens. The males use them like claspers to grab the female during mating.

Dragonfly larvae (LAR-vee) do not look like adults. Their bodies are thick and squat. They breathe with the aid of gills inside the abdomen. The bodies of damselflies are long and slender. Their abdomens are tipped with three leaflike gills used for breathing underwater. The long lower lips of all odonates are hinged at the base and extend forward like an arm. At the end of the lip are two jawlike structures armed with sharp teeth. Larvae capture their prey by thrusting the lower lip forward with blazing speed to grab them. When not in use, the lip is folded underneath the body, leaving the jawlike structures covering the face like a mask.