Dragonfly ( Libellula forensis). Ross Distinguishing characteristics and flight behaviourDragonfly species (Anisoptera) are characterized by long bodies with two narrow pairs of intricately veined, membranous wings that, while generally transparent, may have coloured markings. Unlike damselflies, the front and rear wing pairs are shaped differently.

In addition, dragonflies rest with their wings spread horizontally, rather than held vertically against each other (with the exception of one very small family, Epiophlebiidae). Dragonflies have a more powerful build and are generally much stronger fliers than damselflies. The globe skimmer (or wandering glider, Pantala flavescens), a migratory dragonfly, for example, makes an annual multigenerational journey of some 18,000 km (about 11,200 miles); to complete the, individual globe skimmers fly more than 6,000 km (3,730 miles)—one of the farthest known migrations of all species. Dragonflies also have huge bulging eyes that occupy most of the head, giving some a field of vision approaching 360 degrees. Swift long-winged skimmer ( Pachydiplax longipennis). © Index OpenThe winged adults are diversely coloured in a variety of shades ranging from metallic to pastel. Compared with other insects, they are large, with some having wingspans of up to 16 cm (about 6 inches).

Even the smallest species are about 20 mm (0.8 inch) across. As well as being extremely agile fliers, they are also among the fastest insects. Dragonfly wing muscles must be warm to function optimally, and so, if cool, the insect often engages in wing-whirring and basking in the sun to generate heat before taking flight. The dragonfly’s speed and agility contribute to its being one of the most effective aerial predators. Small flying insects are the usual fare, but some dragonflies regularly consume that is 60 percent of their own weight. Life cycle and reproduction.

The adults of the southern hawker feed on various insects, caught on the wing. This is an inquisitive species and will approach people. These dragonflies breed in still or slow-flowing water. Dragonflies go through incomplete metamorphosis, or a transformation which only has three stages - egg, nymph (or larva) and adult. First, a female adult dragonfly lays its eggs near the calm waters of a pond, swamp or backwater of a river.

Get exclusive access to content from our 1768 First Edition with your subscription.Larvae crawl from eggs laid in or near water. Some species lay their eggs inside plant tissue, others attach their eggs to substrates at or above the water’s surface, and some may drop or wash their eggs from their abdomen onto water. Larvae absorb oxygen from the water using gills inside the. The abdomen draws water in and pumps it out again through the anus. Water can be forcibly expelled in this way, resulting in jet propulsion as a means of escape.

Solid waste is also expelled in this manner. As the larva grows, it molts, its future wings first becoming apparent about halfway through the larva’s development. These wing sheaths then enlarge rapidly with each successive molt. Eventually, the larva crawls out of the water (often at night) and molts one last time, emerging as an adult and leaving behind a cast skin ( ).Dragonflies, like damselflies, exhibit a posture unique to the Odonata. The male and female contort themselves into the “wheel” position before sperm is transferred. Before and after mating, dragonflies often fly in tandem, with the male towing the female in flight using claspers at the tip of his abdomen to grip the back of her head.

Pairs of some species may remain in tandem while the female lays her eggs. Descriptive namesMany dragonfly families have descriptive common names associated with their scientific names. Examples include the hawkers (Aeshnidae), petaltails (Petaluridae), and clubtails (Gomphidae). Numerous other names related to neither nor fact have traditionally been applied to dragonflies, such as horse stinger. Dragonflies have also been known as “snake doctors” in the American South, owing to the superstition that they nurse ill snakes back to health.

The term devil’s darning needle is derived from a superstition that dragonflies may sew up the eyes, ears, or mouth of a sleeping child, especially one who has misbehaved. In reality, dragonflies present no danger to humans.

Contents.Distribution The species is one of the most common and most widespread dragonflies in Europe. The total range is West and covers a large part of Europe (to Scotland and southern Scandinavia in the North to Italy (without the Southwest) and the northern Balkans to the South); the Eastern boundary is formed by the and the West by Ireland. It is also found in Northwest Africa (Algeria).

In Central Europe the species is very common. Habitat These dragonflies mainly inhabit well-vegetated, small ponds and garden ponds, but they wander widely, and they are is often seen in gardens and open woodland. Description. Close-up of head and thorax of a maleAeshna cyanea can reach a body length of about 70 millimetres (2.8 in), with a wingspan up to 110 millimetres (4.3 in). It is a large, brightly coloured dragonfly, with a long body. The thorax is brown, with two ante-humeral wide green longitudinal stripes. On the forehead there is a black spot in the form of the letter T.

The wings are hyaline with a dark. The leading edge of the wings is dark.Males have a dark abdomen with bright apple green markings, except for the last segments S8-10 of the abdomen, where the markings are pale blue and joined. In the females, the abdomen is brownish with bright green markings. The eyes of the males are blue or greenish-blue, while in the females they are yellowish green or brownish.Biology and behavior Flight period of these insects lasts from June to October, with some specimen visible in May and November. The adults of the southern hawker feed on various, caught on the wing. This is an inquisitive species and will approach people.These dragonflies breed in still or slow-flowing water.

The males are often seen patrolling by a ponds edge or river, where they fight away intruders, crashing into rival males and spiralling through the air. The females are quite inconspicuous when they lay their eggs, but they sometimes give away their spot by clattering up from the reeds.The eggs are laid by jabbing the abdomen into rotting vegetation or wood. The eggs hatch in the spring, after being laid in the previous summer or autumn.

The nymphs feed on aquatic insects, small tadpoles, invertebrates and small fish. They emerge as adults in July and August after two-three years’ development.As the possess an which provides support and defends the animal from mechanical injury, but limits growth. Consequently Aeshna cyanea periodically shed in a process referred to as moulting phase.