|
Odonata DAMSELFLIES; DRAGONFLIES; ANISOPTERA; ZYGOPTERA; DRAGONFLIES AND DAMSELFLIES Life Insecta |
IDnature guides |
Overview |
Dragonflies and damselflies, like cockroaches, are one of the oldest types of insects. The only
thing that has changed about dragonflies and damselflies, known as "Odonata," are their size. In
prehistoric times, when dinosaurs could be found roaming the earth, odonata were as big as hawks.
Odonate fossils have been discovered in Kansas, Siberia, and many other parts of the world. They
had wingspans of about thirty inches and were the largest insects to ever live.--
(Nature Sketches)
| Dragonflies and damselflies are fairly large flying insects. They are often very colorful and are carnivorous - they hunt and eat meat. Even though they can fly, odonates are considered aquatic insects because they live near fresh water and their larvae (young form) actually live in water. Dragonflies have been an extremely popular subject of folklore in many cultures, most notably Japan. In Europe they have been regarded as dangerous, but they neither sting nor bite and are in fact completely harmless to humans. Actually, odonates are in some ways beneficial as predators because they can be used to control pests. The quality of the environment can be somewhat monitored by odonates because their presence is strongly affected by different factors such as waterflow, pollution, and vegetation. Odonate larvae are sometimes used as bait by fishermen, and adults are a minor food item in some countries, but other than that dragonflies are of little economic importance.-- (Tree of Life) Click here for Dragonfly checklist in the Great Smoky Mountains.
Identification |
Characteristics: Adults | In general, the head of the adult is large and is dominated by the compound eyes. The face carries a pair of very short antennae. The thorax is skewed (small in front and large in back), which enhances perching and grasping abilities. The legs are strong enough to perch or hold prey but not suitable for walking. The abdomen is long (at least the length of one wing), flexible, and divided into ten segments. Both male and female odonates have clasping organs at the end of the abdomen. The females sometimes have an ovipositor under abdominal segments 9-10 with which to lay their eggs, and the males always have secondary genitalia under segments 2-3. Damselflies (Zygoptera), for the most part, appear more fragile than dragonflies (Anisoptera). Dragonflies rest with their wings pointed straight out to the sides, while damselflies usually rest with their wings more upward, fitting neatly along the top of the abdomen. Odonata cannot fold their wings over the body like most insects. -- (Tree of Life)
Phylogeny |
|
Common names & synonyms The name "Odonata," created by a man named Fabricus in 1793, comes from Latin and means "toothed." The family name Libellula may have been derived from the Latin "libella" which means "booklet," and with some imagination, a resting dragonfly can look like a small booklet. Odonata have widely been objects of superstition. In Germany, odonata have had over 150 different names, including names that mean "devil's needle," "water witch," "goddess' horse," "devil's horse," and "snake killer." In England, names meaning "devil's darning needle" and "horse stinger" have been used. In Denmark, some names mean "devil's riding horse" and "goldsmith." A Swedish name means "hobgoblin fly"; long ago, the people in Sweden believed that goblins, elves and fairies lived in the woods and used dragonflies as twisting tools. Another Swedish name means "blind stinger," and comes from the belief that dragonflies can pick out your eyes or even sew them shut. Also, odonata have obviously been connected to females: "damselfly." The body shape of odonata have led them to earn names than mean "devil's steelyard" and such because they look like heavy tools. The myth is that the Devil uses them to weigh a persons soul, and when a dragonfly flies around your head, you should expect serious punishment. On the other hand, dragonflies are also thought to to beneficial. In Scandinavia, one cult worships the dragonfly as a symbol of a love goddess. Dragonflies are caught to be fried or eaten in soups in such places as Indonesia, Africa, and South America. In China and Japan, odonata are treated as holy creatures and are believed to have medicinal properties. The species Sympetrum frequens is actually used to help reduce fever. -- (Dragonfly Folklore) |
Aeshna multicolor Photo copyright C. Williams |
Gomphus militaris Photo copyright C. Williams |
Erythemis spp. larva Photo copyright Dave McShaffrey |
Helocordulia selysii Photo copyright C. Williams |
Aeshna multicolor Photo copyright C. Williams |
Calopteryx maculata Photo copyright Dave McShaffrey |
Helocordulia selysii Photo copyright C. Williams |
Amoesta spp. Photo copyright University of Michigan |
Aeshna multicolor Photo copyright Steven A. Valley |
Aeshna multicolor female Photo copyright Steven A. Valley | ||
Libellula saturata male Photo copyright Steven A. Valley |
Aeshna interrupta Photo copyright University of Puget Sound |
Odonate larvae are not choosy hunters; they will eat any animal as large or smaller than themselves, including tadpoles, fish fry, and even other odonate larvae. The larvae move by a type of jet propulsion in which they squirt water out to create a moving force. As they grow, larvae undergo about ten to twenty molts. After the final molt, they emerge as an adult; there is no pupal stage. Emergance takes place on a fixed support out of water. Young adults, which can be recognized by a glassy sheen on the wings, fly away from water for a while to feed and mature, and some develop new color.
Adult odonata have well-developed eyes and hunt mostly by sight. They are also extremely agile fliers and catching one can be even more difficult than capturing a housefly. Adult males generally hang out near water to be seen by females, who mostly stay away from water until they are ready to mate and lay eggs.
In mating, the male and female form a 'wheel' position: The male gets in front and clasps the head of the female with the claspers at the end of his abdomen; the female is behind and bends her abdomen downward to the secondary genitalia of the male where she will receive his sperm. Dragonflies can mate while perched but can also (and often do) mate while in flight. The male is often present while the female lays her eggs so that other male competition will not disturb her. The female uses her ovipositor to lay the eggs on or into aquatic plants. If she does not have an ovipositor, she will disperse her eggs on the surface of the water. -- (Tree of Life)
Odonata adults need sunshine and warmth for their daily activity, and that is why you never see them on cold or cloudy days. Many species must therefore warm themselves before they fly, and they do this in two ways. First, they bask in the sunlight at right angles to the sunlight so they can get the most out of the suns rays. Second, when they are perched, they rapidly shiver their flight muscles, which creates heat. Some large odonata can overheat on hot days. To prevent this, they begin to make longer glides between wing beats (Miller, 1987).
There are many interesting facts and misconceptions about odonata biology and behavior. Many people believe that odonata live for only one day. This is not true. The odonata life-cycle can be from a few months to even a several years. One fascinating fact is that they can fly up to speeds of 25-30 miles per hour. Also, adult odonata will feed on mosquitoes, which can be good, yet they even eat butterflies. Some will even take spiders from their webs! As mentioned before, odonata antennae are extremely small. They rely mostly on their large eyes rather than their senses of touch or smell. Odonata can sometimes be seen flying in large swarms and this is probably due to either good feeding conditions in the area or a mass migration (like those of birds). -- (British Dragonfly Society)
How to encounter:
Odonates can be found in almost any type of freshwater habitat since they breed in these areas. Look
for them near rivers, lakes, streams, ponds, and even marshes and swamps.
Top
Updated: 2024-10-04 14:42:06 gmt © Designed by The Polistes Corporation |