Dragonfly Song

Currently there's a dizzying array of dragonflies to be seen around the joint. I've already done a bit of a post on 'em (My Favourite Animal), so I thought I'd simply put up a few pics of just some that I've snapped recently along with a few tasty wiki snippets:

Slender Skimmer (Orthetrum sabina) or Green Skimmer (Orthetrum serapia) click to enlarge

Loss of wetland habitat threatens dragonfly populations around the world. Dragonflies are represented in human culture on artifacts such as pottery, rock paintings, and Art Nouveau jewellery. They are used in traditional medicine in Japan and China and are caught for food in Indonesia.

Common Glider (Trapezostigma loewii)

Dragonflies are powerful and agile flyers, capable of migrating across oceans, moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions: upward, downward, forward, backwards, left and right.

The wings are powered directly, with the flight muscles attached to the wing bases. Dragonflies have a high power/weight ratio, and have been documented accelerating at 4G linearly and 9G in sharp turns while pursuing prey.

Unknown - Huge

Dragonflies are hemimetabolous insects; they do not have a pupal stage and undergo an incomplete metamorphosis with a series of nymphal stages from which the adult emerges. Eggs laid inside plant tissues are usually shaped like grains of rice, while other eggs are the size of a pinhead, ellipsoidal, or nearly spherical.

A clutch may have as many as 1500 eggs, and they take about a week to hatch into aquatic nymphs or naiads which moult between six and 15 times (depending on species) as they grow.

Yellow-striped Flutterer (Rhyothemis phyllis) click to enlarge

In high-speed territorial battles between male Australian emperors (Hemianax papuensis), the fighting dragonflies adjust their flight paths to appear stationary to their rivals, minimizing the chance of being detected as they approach.

To achieve the effect, the attacking dragonfly flies towards his rival, choosing his path to remain on a line between the rival and the start of his attack path. The attacker thus looms larger as he closes on the rival, but does not otherwise appear to move. Researchers found that six of fifteen encounters involved motion camouflage.

Neurothemis stigmatizans

If you're looking to I.D dragonflies here in Au, this is an excellent resource
Dragonfly Identification Key

A dragonfly is an insect belonging to the order Odonata, suborder Anisoptera (from Greek ἄνισος anisos "uneven" and πτερόν pteron, "wing", because the hindwing is broader than the forewing). Adult dragonflies are characterized by large multifaceted eyes, two pairs of strong transparent wings, sometimes with coloured patches and an elongated body. Dragonflies can be mistaken for the related group, damselflies (Zygoptera), which are similar in structure, though usually lighter in build; however, the wings of most dragonflies are held flat and away from the body, while damselflies hold the wings folded at rest, along or above the abdomen. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight. Many dragonflies have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. An adult dragonfly eye has nearly 24,000 ommatidia.

Fossils of very large dragonfly ancestors in the Protodonata are found from 325 million years ago (Mya) in Upper Carboniferous rocks; these had wingspans up to about 750 mm (30 in). About 3000 species of Anisoptera are in the world today. Most are tropical, with fewer species in temperate regions.