Dragonflies — Facts, Information — Pictures

Dragonflies, Facts and Photos

A dragonfly is an insect belonging to the order ‘Odonata’. Dragonflies are are not actually a fly even though they both have six legs and three body parts, head, thorax and abdomen. The main difference between them is that flies only have two wings whereas dragonflies have four wings. Dragonflies are sometimes confused with Damselflies.

Even though they are both members of the same order, they have slight differences whereby when resting, damselflies hold their wings together, a dragonfly holds its wings horizontally or slightly down and forward and their hindwings are broader near the base.

The eyes on a damselfly are separated, in most dragonflies the eyes touch. However, being in the same order makes their life cycles quite similar. The Dragonfly name comes from their fierce jaws, which they use to catch their prey.

Characteristics

A Dragonfly has two large compound eyes which take up most of its head. Dragonflies have long, delicate, membranous wings which are transparent and some have light yellow colouring near the tips. Their bodies are long and slender and they have a short antennae.

Dragonflies are very colourful, for example the Green Darner Dargonfly has a green thorax and a blue segmented abdomen. Some are red like the Comet Darner and yellow like the Emerald Darner.

Dragonflies breath through spiracles which are tiny holes located on their abdomen. They can beat each pair of wings together or separately and their rear wings can be out of phase with the front wings. Their wing beat is around 50 – 90 beats per second.

Dragonflies have complicated neck muscles which allow them to tilt their head sideways 180 degrees, back 70 degrees and down 40 degrees.

Dragonflies can hover in mid air and then rapidly accelerate. Traveling at almost 30 miles per hour, dragonflies are the fastest insects in the UK.

Dragonfly Diet and Vision

All dragonflies are carnivorous in both the larval and adult stages of their lives. Dragonflies typically eat mosquitoes, midges and other small insects like flies, bees and butterflies, catching its prey while it is flying. A Dragonflies ability to manoeuvre in many directions makes them able to out-fly their prey.

Dragonfly

Dragonflies also have the advantage of excellent eyesight. Each of their two large eyes is made up of thousands of six-sided units. Together, these smaller eyes enable a dragonfly to detect even the slightest movement. They have large optic brain lobes and 80% of their mental processes are devoted to vision and they can detect colour, ultraviolet light and polarization.

Habitats

Dragonflies are usually found around water such as lakes, ponds, streams and wetlands because their larvae, known as ‘nymphs’, are aquatic.

Reproduction

A dragonfly undergoes incomplete metamorphosis. Female dragonflies lay eggs in or near water, often on floating or emergent plants. When laying eggs, some species will submerge themselves completely in order to lay their eggs on a suitable surface. After about two weeks, the eggs hatch and an immature dragonfly, or nymph, emerges. The nymphs are not as attractive as the adults. They have tiny wings and a large lower lip, which they use to catch their prey (often mosquito larvae).

Dragonfly

Dragonfly nymphs live in the water. As they grow, they molt (shed their skin). Nymphs of some species may take as long as three years to mature. Most of a dragonflys life is spent in the larval stage beneath the waters surface, using internal gills to breathe and using extendable jaws to catch other invertebrates or even vertebrates such as tadpoles and fish. The life span ranges from about 6 months to over 7 years (most of it is spent in the nymph stage – the adult lives for only a few weeks).

When the larva is ready to metamorphose into an adult, it climbs up a reed or other emergent plant at night. Exposure to air causes the larvae to begin breathing. The skin splits at a weak spot behind the head and the adult dragonfly crawls out of its old larval skin, waits for the sun to rise, pumps up its wings and flies off to feed on midges and flies.

Dragonflies and Humans

Dragonflies do not normally bite or sting humans, although they will bite in order to escape, if grasped by the abdomen. They are valued as predators that help control populations of harmful insects, such as mosquitoes. Dragonflies are one of several insects commonly referred to as ‘mosquito hawks’ in North America.

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Dragonfly History

Dragonfly

The oldest known species of dragonfly is the 320 million year old (Delitzschala bitterfeldensis). Another is ‘Namurotypus’ an extinct genus of dragonfly. Dragonflies are ancient insects. They were around before the dinosaurs. Ancient dragonflies may have been considerably larger than those we see today. A fossilized impression of a dragonfly wing, found in a coal mine in England, is the oldest known dragonfly specimen. This dragonfly lived 320 million years ago and had a wingspan of 8 inches. The largest known dragonfly had a wingspan of 24 inches (two feet). Today, the largest dragonfly is found in South America and has a wingspan of slightly over seven inches. Other than being smaller, modern-day dragonflies do not look very different from their ancestors.

Conservation

Fifty years ago there were twice as many ponds in Britain as there are today. The draining of agricultural land, filling in and pollution have all contributed to the disappearance of most countryside ponds. Canals have also suffered from pollution, especially by chemicals used on farmland draining into water. The loss of suitable fresh water habitats has affected dragonflies enormously and they are becoming increasingly rare. The Norfolk aeshna, Aeshna isosceles, which can be found living only in the Norfolk Broads, is on the list of Britains endangered species of insects.

Helping Dragonflies

Garden ponds have become very popular over recent years and these are helping to save Britains threatened pond-life including dragonflies. Creating a pond habitat in your garden at home, or in your school grounds, is a practical and worthwhile conservation project.

animalcorner.org

14 Fun Facts About Dragonflies

Dragonfly

Flying insects are usually annoying. Mosquitoes bite you, leaving itchy red welts. Bees and wasps sting. Flies are just disgusting. But there’s something magical about dragonflies.

  1. Dragonflies were some of the first winged insects to evolve, some 300 million years ago. Modern dragonflies have wingspans of only two to five inches, but fossil dragonflies have been found with wingspans of up to two feet.
  2. Some scientists theorize that high oxygen levels during the Paleozoic era allowed dragonflies to grow to monster size.
  3. There are more than 5,000 known species of dragonflies, all of which (along with damselflies) belong to the order Odonata, which means “toothed one” in Greek and refers to the dragonfly’s serrated teeth.
  4. In their larval stage, which can last up to two years, dragonflies are aquatic and eat just about anything—tadpoles, mosquitoes, fish, other insect larvae and even each other.
  5. At the end of its larval stage, the dragonfly crawls out of the water, then its exoskeleton cracks open and releases the insect’s abdomen, which had been packed in like a telescope. Its four wings come out, and they dry and harden over the next several hours to days.
  6. Dragonflies are expert fliers. They can fly straight up and down, hover like a helicopter and even mate mid-air. If they can’t fly, they’ll starve because they only eat prey they catch while flying.
  7. Dragonflies catch their insect prey by grabbing it with their feet. They’re so efficient in their hunting that, in one Harvard University study, the dragonflies caught 90 to 95 percent of the prey released into their enclosure.
  8. The flight of the dragonfly is so special that it has inspired engineers who dream of making robots that fly like dragonflies.
  9. Some adult dragonflies live for only a few weeks while others live up to a year.
  10. Nearly all of the dragonfly’s head is eye, so they have incredible vision that encompasses almost every angle except right behind them.
  11. Dragonflies, which eat insects as adults, are a great control on the mosquito population. A single dragonfly can eat 30 to hundreds of mosquitoes per day.
  12. Hundreds of dragonflies of different species will gather in swarms, either for feeding or migration. Little is known about this behavior, but the Dragonfly Swarm Project is collecting reports on swarms to better understand the behavior. (Report a swarm here.)
  13. Scientists have tracked migratory dragonflies by attaching tiny transmitters to wings with a combination of eyelash adhesive and superglue. They found that green darners from New Jersey traveled only every third day and an average of 7.5 miles per day (though one dragonfly traveled 100 miles in a single day).
  14. A dragonfly called the globe skinner has the longest migration of any insect—11,000 miles back and forth across the Indian Ocean.

www.smithsonianmag.com

5 Myths About Dragonflies

Are Dragonflies Evil?

The ancient insects we call dragonflies may be the most misunderstood insects of all. Some cultures revile them, while others revere them. Many myths have emerged over the centuries, and some still get handed down from generation to generation. Here are 5 myths about dragonflies, with facts to set the record straight.

1. Dragonflies Live Just One Day

Dragonflies actually live for months or even years, if you count the entire life cycle from egg to adult. In some species, the aquatic nymphs molt up to 15 times, a growth process that takes several years to complete. People who think dragonflies live just one day are probably thinking only of the adult dragonfly stage. It is true that an adult dragonfly’s main objective is to mate before dying, and so they don’t need to live very long. But most adult dragonflies will live for several months at least while eating, patrolling, and mating. Dragonflies don’t usually die of old age, either – they tend to wind up in the bellies of larger predators, like birds.

2. Dragonflies Sting

Nope, not even close to true. Dragonflies may look threatening to the entomophobes among us, but there isn’t a dragonfly known to man that has a sting apparatus. Male dragonflies do bear claspers for holding the female during mating, and these could perhaps be mistaken for a stinger by an uninformed observer. Also, in some female dragonflies – the darners and petaltails, specifically – the ovipositor is designed to slice open plant stems. These dragonflies, as well as all of the smaller and less intimidating damselflies, insert their eggs into plant material and are thus equipped to incise plant tissue. Now, on very rare occasions, a dragonfly has mistaken someone’s leg for a plant and attempted to slice it open and deposit an egg. Yes, that hurts. But that doesn’t mean the dragonfly can sting. There are no venom sacs to administer toxins into your body, and the insect’s intent is not to harm you. Only insects in the order Hymenoptera (ants, bees, and wasps) can sting.

3. Dragonflies Can Sew Your Mouth (or Ears or Eyes) Shut

Although it is kind of fun to tell little kids they can. People perpetuating this myth refer to dragonflies as «Devil’s darning needles,» and usually offer it as a caveat to children who are misbehaving. If there was any logical origin of this not-so-urban legend, it probably lies in the same morphological features that make people think dragonflies can sting. Just because an insect has a long, pointy abdomen does not mean it can employ a running stitch to sew up your mouth.

4. Dragonflies Harass Horses

The horses might feel as if they are being harassed when dragonflies persistently fly around them, but the dragonflies have no particular interest in the horses. Dragonflies are predaceous, feeding on other, smaller insects, including the flies that tend to hang around horses and cattle. In all likelihood, a dragonfly that seems to be fixated on a horse is simply improving its odds of catching a meal. People sometimes call dragonflies «horse stingers,» but as we’ve already established, dragonflies don’t sting at all.

5. Dragonflies Are Evil

For centuries, people have eyed dragonflies with suspicion and imbued them with evil intent. Swedish folk legends accused dragonflies of poking out people’s eyes and referred to them as «blind stingers» for this reason. From Germany to England, people associate dragonflies with the devil, giving them nicknames like «water witch,» «hobgoblin fly,» «devil’s horse,» and even «snake killer.» That one is particularly interesting since snakes themselves are often thought to be in cahoots with Satan. But truth be told, dragonflies are far from evil. They are, in fact, quite beneficent, if we consider how many mosquitoes they consume, both as nymphs (when they eat mosquito larvae) and adults (when they catch and eat them in flight). If we’re going to call the Odonates by any nickname, «mosquito hawk» is the one we’d prefer to use.

www.thoughtco.com

Dragonflies: Facts, Symbolic Meaning, and Habitat

Age-Old Wisdom meets Modern Tools

Dragonfly

The dragonfly and its smaller cousin, the damselfly, belong to an ancient order of insects known as Odonata and have carried symbolic meaning for centuries. Most people love to have dragonflies in their gardens, if only because dragonflies love to eat mosquitoes.

Who hasn’t marveled at the aerial abilities of dragonflies as they glide effortlessly over sparkling streams, pristine ponds, and lakes, plucking insects from the air with deadly precision?

Dragonfly Facts and Life Cycle

Dragonfly

Surprisingly, these brilliantly colored masters of the air are classified as aquatic insects because they spend most of their lives as larvae underwater among plants or in silt. They may spend five years or more in the larval stage, molting several times before emerging as adults—and then living only a few weeks to a few months.

With keen eyesight and expert airmanship, dragonflies and damselflies easily outmaneuver and catch insect prey. Their four gossamer wings move independently of one another, giving them the ability to fly forward, backward, and sideways, or to just hover in place. Bead-like eyes provide 360–degree stereovision, allowing them the ability to spot insects in any direction without turning or moving their heads. (In fact, dragonflies have the biggest eyes in the insect world.)

Dragonflies and damselflies, though similar in their life cycle and appearance, fly differently. You can distinguish them by noticing that dragonflies fly directly and with purpose, while the damselfy’s flight is more fluttery. The damselfly also has a slightly longer abdomen.

A damselfly has the same captivating appearance as a dragonfly, but it is a bit smaller and its eyes are farther apart.

What do dragonflies eat? The dragonflies’ and damselflies’ fondness for mosquitoes puts them in the category of beneficial insects, but they eat many other annoying bugs. Their diet includes midges, moths, flies, and other flying insects. Unfortunately, they also sometimes eat butterflies. This means that planting flowers that attract butterflies might keep your yard full of both species.

Dragonflies aren’t just beneficial as mosquito-eaters. Their role as barometers of wetland health is also very important. In order to survive, odonate larvae need clean, well-oxygenated water. Drainage of wetlands, pollution from farming and industry, and the development of new roads and houses have increasingly reduced dragonfly habitat. Conservation of existing wetlands is key to odonate survival, as is providing new habitats for them to colonize.

Fossil records show that dragonflies were around for 100 million years before the dinosaurs. These prehistoric predators had wingspans of over three feet and are the largest insects known. Imagine if they were that big now—a dainty dragonfly landing on your finger would not seem quite so charming!

Dragonfly Meaning and Symbolism

Dragonfly

  • Many Americans believe that it is good luck if a dragonfly lands on you without prompting. Dragonflies are also a symbol of good luck in Chinese tradition.
  • Dragonflies have been a notable part of folklore in many countries, especially Japan. Japanese tradition views dragonflies as symbols of swiftness and as a sign of summer and autumn.
  • Dragonflies have been a symbol of purity, activity, and swiftness for some Native Americans. The indication of purity comes from both the pure water in healthy aquatic habitats where dragonflies thrive and from the fact that they eat their food right out of the wind.
  • Some common names for dragonflies are “Mosquito Hawk,” “Devil’s Darning Needle,” and “Snake Doctor.” Mosquito Hawk stems from the dragonfly’s favorite food, Devil’s Needle stems from very old traditions indicating that dragonflies were evil, and Snake Doctor stems from the fact that dragonflies can often be seen in the same habitat as snakes and sometimes even interact with them.

How to Attract Dragonflies to Your Garden

  • Constructing a pond or other backyard water feature will attract a surprising number of dragonflies and damselflies. Size is not crucial, but dig the basin deep enough so that the water won’t freeze solid in the winter. Plant a few native plants at its edge for wind protection. The pond should get at least partial sun.

Dragonflies are born and spend most of their lives in aquatic habitats, so you can attract them by building a pond in your yard.

  • If you already have a pond in your yard or are considering building one, it helps to have some vertical plants coming out of the water. This is where the female dragonflies and damselflies will lay their eggs.
  • By providing needed habitat, you can help save dragonflies as well as damsels in distress.
  • Be aware of the pesticides you are using to get rid of annoying bugs like mosquitoes—they also might be harming beneficial insects like dragonflies. Look at our tips for how to deter mosquitoes instead. Remember that if you’re not controlling the mosquito population, hopefully the dragonflies will!
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