Dragonflies and damselflies, which together form the insect Order Odonata, have aquatic immature stages that live in a variety of freshwater habitats. The adults are common around rivers, streams, lakes, ponds, swamps and even temporary pools. However, strong-flying and migratory species may be found far from water.
Damselflies and dragonflies have two pairs of stiff, wings with a dense network of veins. Most fly during the day but some are active only at dusk and dawn (crepuscular). All are predators, catching insects on the wing, or gathering them and spiders from vegetation. Their large eyes give them excellent vision. All of their spiny legs are directed forwards under their heads so they can easily grasp prey and consume it while still flying.
Females lay eggs on the surface of water or insert them into the stems of water plants or soft mud. Their immature stages, or nymphs, are also predatory, feeding on aquatic invertebrates, tadpoles and even small fish. The nymphs have an extendible bottom lip which can be shot out to capture prey. When the nymphs are fully grown they crawl out of the water onto protruding rocks or vegetation where the adult emerges. In several species, newly emerged and mature adults differ in coloration, with powdery deposits developing on the body with age.
There are 324 species of dragonflies and damselflies in Australia.
A freshly emerged adult dragonfly hangs from the shed skin of its final nymphal stage. The pale body of the dragonfly is yet to harden.
What’s the difference between dragonflies and damselflies?
All damselflies have eyes that are far apart and forewings and hindwings of similar shape. Most damselflies rest with both pairs of wings held together over their abdomens, although some hold their wings flat on either side of the body.
Dragonflies are generally more robust than damselflies. Most have the eyes touching at the top of the head, although they are clearly separated in some species. The forewings and hindwings of dragonflies are different in shape, particularly at their bases. Most dragonflies rest with their wings held out flat, although a few hold them together over their abdomens.
Most dragonflies have large eyes that touch at the top of the head. These give them almost 360 degree vision.
An Australian Tiger, Ictinogomphus australis, one the small number of dragonflies in which the eyes are clearly separated.
A Whitewater Rockmaster, Diphlebia lestoides. These damselflies frequent rainforest streams and are unusual because they rest with their wings out flat.
A Common Bluetail, Ischnura heterosticta. These damselflies are found throughout Australia.
A Blue Skimmer, Orthetrum caledonicum. These dragonflies develop a blue powdery deposit on their body with age.
Useful books and websites on Australian dragonflies and damselflies include:
The Complete Field Guide to Dragonflies of Australia (2006) by Günther Theischinger and John Hawking, CSIRO PUBLISHING
Identification of the aquatic larvae of Odonata from the Murray Darling Research Centre. Has a link to a key at the bottom of the page.
Odonata of the Murray Darling Basin – gives a very good outline on the biology of dragonflies.