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Dragonflies
Artwork by: Joann Wheeler 2001

Fast Fact:

The suborder name of Anisoptera means "unequal wings". The wingspan of some fossilized dragonflies can be over two feet!

Size 12.7 to 25.4 mm, to 1 inch
Habitat Generally, dragonfly larvae are bottom dwellers. Many species live in areas of standing water such as permanent or temporary ponds, lake edges, swamps and marshes. A few species live in the soft sediments, bank vegetation or bank debris of streams. When disturbed, dragonfly larvae can move quickly to safer habitats by expelling water out their rectal chambers. Some species are excellent swimmers and use their rectal chambers as jet propulsion systems.
Reproduction Dragonflies are a hemimetabolous order with all species having aquatic larvae. The dragonfly life cycles can take up to four years to complete! Adults disperse and feed for a week or more before returning to breeding sites. At the breeding sites, a male chases other males out of his territory while trying to capture a female when she has entered his territory. After he captures a female, mating occurs. Soon, the female lays eggs one by one inside plant tissues that are below, at or above the surface of the water. Eggs can also be laid one by one or in a large mass on plants, debris or other underwater structures, or laid on the surface of the water (they later sink to the bottom). After the larvae hatch, they crawl out of the water and dry off. Once their exoskeleton dries and cracks, the adult climbs out of the exoskeleton and flies away in search of a mate. Generally, the adult stage only lasts up to few weeks.
Feeding Dragonfly larvae are predators that mostly feed on other small invertebrates, shrimp, small fishes and larval amphibians. As a result, dragonfly larvae are key predators in invertebrate communities. Adults are also predators feeding on mosquitoes and other flying insects, such as black flies (Simuliidae) and horse flies and deer flies (Tabanidae).
Predators There are many potential predators at all stages of life. Larvae are prey to larger predatory insects, fish, frogs, turtles and birds. When larvae emerge from the water to metamorph into adults, they are still soft and cannot fly well. As a result, newly emerged larvae are vulnerable to birds and frogs. Birds and frogs will also feed on larvae and adults when they become concentrated into small pools as a result of a drought. Adults flying into a spider’s web may become trapped and food for the spider.
Description Dragonfly larvae are easily distinguished from other insect larvae. Larvae are elongated with a hinged labium, large eyes and short antennae. Some species of dragonfly larvae are covered with coarse "hairs".  Larvae have three triangular-shaped pointed appendages at the end of the abdomen. Colors typically reflect their surrounding habitat (mostly brown). Gills are found inside the rectal chamber. Movement of water in and out of this chamber greatly enhances respiration allowing dragonfly larvae to reside in areas of standing water where dissolved oxygen levels may be less suitable to other aquatic organisms. Coloration in adults ranges from brown and black to green, red and blue. Adults do not resemble larvae in that they have very elongated abdomens and two pairs of large veined wings. Adult dragonflies can be distinguished from adult damselflies in two ways: 1) adult dragonflies have much larger and thicker bodies than adult damselflies; and, 2) adult dragonflies hold their wings horizontally in relation to the abdomen when at rest, while adult damselflies hold their wings vertically in relation to the abdomen when at rest. Neither insect can fold its wings.

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