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The
Diversity of The World of Life
True
Insects (Insecta)
Dragonflies &
Damselflies
(Odonata)
Representatives
Dragonflies
& Damselflies
Biology
APPROXIMATE NUMBER OF KNOWN SPECIES WORLDWIDE
5,000
DESCRIPTION
Dragonflies and damselflies are usually large, colorful,
very slender insects. The
antennae are very short. The
compound eyes are very large. The mouthparts are chewing.
The wings, with many cross veins, are held at rest either outstretched from the body (in dragonflies) or
upright over the body (in damselflies). The forewings and hindwings
are about the same size and shape as each other (although the hindwing of a dragonfly is broader at the
base than the forewing). The abdomen of damselflies
is more slender than that of dragonflies.
METAMORPHOSIS
The adults mate in flight.
The eggs are laid in logs, in the stems of aquatic plants, or
directly in the water. The
"naiads" (aquatic nymphs) develop small wing pads and have
gills, either on the tail (of damselfly naiads) or in the rectum (used in the jet-propulsion of dragonfly
naiads).
The naiads live on the bottom of bodies of water or in
plants or debris in the water. The
naiads eventually crawl out of the water and onto such objects as stems,
for their final molt, into the winged adult.
HABITATS
The naiads live in ponds and streams, and the adults often
live nearby but sometimes fly miles away.
FOODS
The naiads use a tongue-like structure to grab small, aquatic prey; and the adults
use their legs and jaws to catch small insects, often in flight.
DAMAGES/BENEFITS
Dragonflies and damselflies are generally beneficial.
Most of the naiads are predators of other aquatic insects,
such as mosquito larvae; some are predators of tadpoles and small fish
(sometimes, unfortunately,
in hatcheries); and many are themselves valuable prey of game fish.
A few of the insects in this group carry certain
"flukes" (parasitic flat
worms) to frogs, wild waterbirds,
poultry, and other animals.
Adult
dragonflies and damselflies are usually beneficial as predators of small
flying insects, but the adults of large species are sometimes serious
pests of honey bees. And the bite of large species can be painful to
us human beings.
True
Insects (Insecta)
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