Dragonflies are large and heavy-bodied insects. They usually hold their wings open and flat when perched, just like the dragonfly in the picture above. Their eyes are close together, often touching. Young dragonflies (or Nymphs) develop in water and move by what looks like jet propulsion.
Dragonflies eat the larvae of other insects that live in the water – including mosquito larvae. One of the benefits of having dragonflies live nearby is that they eat many times their weight in mosquitoes every day. Dragonflies also eat other kinds of flies and the occasional honeybee. Using a basket-like arrangement of their legs, adult dragonflies can actually catch and eat other bugs while they are flying.
How are Dragonflies beneficial?
Adult dragonflies eat other flying insects, particularly midges and mosquitoes. They also will eat butterflies, moths and smaller dragonflies. There is one Asian species which eats spiders from their webs! The larvae, which live in water, eat almost anything living that is smaller than themselves. The larger dragonfly larvae are known to catch and eat small fish or fry. Usually they eat bloodworms or other aquatic insect larvae.
What enemies do Dragonflies have?
Dragonflies do have enemies. Among the species that catch and eat adult dragonflies and damselflies are birds (e.g. Wagtails and Hobbies), Spiders (many damselflies are caught in webs), Frogs, and larger species of dragonflies (which catch and eat other dragonflies and damselflies).
In the larval stage, which is spent underwater, they are preyed on by fish, frogs, toads and newts, and other water invertebrates. Their defenses include their excellent eyesight and flying skills which can help them to evade capture. Some are colored black and yellow, or black and red, which is the universal warning coloration and may deter some of the bird predators.
What is the lifecycle of the Dragonfly?
Greatly simplified, the life cycle is Egg (usually laid under water), Larva (free moving, water dwelling nymph) and Adult.
The larva lives for several weeks (or years depending on species) underwater and undergoes a series of molts as it grows. It emerges from the water when it is ready to undergo its final molt where the “skin” splits to reveal the winged adult.
How big is a dragonfly?
Dragonflies come in many sizes. The average size of a dragonfly is from
1 to 4 inches in length. Although mostly found near ponds and streams, they are very skilled fliers and can fly miles from a water source. Because they are such strong fliers; a few kinds of dragonflies even migrate.
In prehistoric times dragonflies were much larger, the largest flying insects ever. The largest member of extinct Dragonflies had a wing span of about 70-75 cm or about 30 inches.
How long do Dragonflies live? Is it true that they only live for one day?
At the shortest, a dragonfly’s life-cycle from egg to death of adult is about 6 months. Some of the larger dragonflies take 6 or 7 years! Most of this time is spent in the larval form, beneath the water surface, catching other invertebrates.
Do Dragonflies Bite or Sting?
No. I you hold a very large dragonflies in the hand will sometimes try to bite, they fail to break the skin. They have a lot of “folk names” which imply that they do bite (such as Horse stinger). However, not even the largest dragonflies bite people. They are a fearsome predator of other flying insects.
Why do Dragonflies sometimes appear in large swarms?
Several species of dragonfly are known to collect in large swarms. In most cases this appears to be due to very favorable feeding conditions in the area. It may also be a “courting” group with males actively searching for females. This is less likely as males are much more aggressive to each other when looking for a mate.
Some dragonflies gather in swarms before moving to a new area (like a bird migration). The reasons for this are unclear but may be due to population pressures. There are records from the US of migratory swarms.