|
| [Note Guidelines] Photographer's Note |
A dragonfly is any insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera. It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body.
Dragonflies typically eat mosquitoes, midges and other small insects like flies, bees, and butterflies. They are usually found around lakes, ponds, streams, and wetlands because their larvae, known as "nymphs", are aquatic. Dragonflies do not normally bite or sting humans (though they will bite in order to escape, for example, if grasped by the abdomen); in fact, they are valued as a predator that helps control the populations of harmful insects, such as mosquitoes.
Life cycle
The life cycle of the dragonfly, from egg to death of adult, varies from six months to as much as six or seven years. Female dragonflies lay eggs in or near water, often in or on floating or emergent plants. Most of the life cycle is spent in the larval (naiad, aka nymph) form, beneath the water surface, using internal gills to breathe, and catching other invertebrates or even vertebrates such as tadpoles and fish. In the adult (flying) stage, larger species of dragonfly can live as long as four months.
General facts
Much larger dragonfly species existed in the distant past than occur on earth today. The largest one, found as a fossil, is an extinct Protodonata named Meganeura monyi from the Permian period with a wingspan of 70–75 cm (27.5–29.5 in). This compares to 19 cm (7.5 in) for the largest modern species of odonates, the Hawaiian endemic dragonfly, Anax strenuus. The smallest modern species recorded is the libellulid dragonfly, Nannophya pygmaea from east Asia with a wingspan of only 20 mm, or about ¾ of an inch.
Dragonflies have very good eyesight due to their eye structure. Dragonflies have up to 30,000 facets to their compound eyes; each one is a separate light-sensing organ or ommatidium, arranged to give nearly a 360° field of vision.
The oldest known dragonfly is the 320 million year old Delitzschala bitterfeldensis. Another old genus is Namurotypus.
From Wikipedia, the free encyclopedia |
lctan has marked this note useful
Only registered TrekNature members may rate photo notes. |
|
![Gold Star Critiquer/Gold Workshop Editor/Silver Note Writer [C: 54 W: 99 N: 26]](https://i1.treknature.com/misc/g-g-s.gif){kind=small}