They, like the gigantic predinosaur griffinflies, lack the ability to fold their wings up against their bodies in the way modern insects do, although some evolved their own different way to do so. Modern dragonflies do retain some traits of their distant predecessors, and are in a group known as the Palaeoptera, ancient-winged. While both of those groups are sometimes referred to as "giant dragonflies", in fact true dragonflies/odonata are more modern insects that had not evolved yet.įurther information on the extinct genus of dragonfly: Libellulium The Protanisoptera, another ancestral group that lacks certain wing-vein characters found in modern Odonata, lived from the Early to Late Permian age until the end Permian event, and are known from fossil wings from current-day United States, Russia, and Australia, suggesting they might have been cosmopolitan in distribution. Known informally as "griffinflies", their fossil record ends with the Permian–Triassic extinction event (about 247 Mya). Museum of Toulouse Mesurupetala, Late Jurassic ( Tithonian), Solnhofen limestone, Germany Dragonflies in Oze National Parkĭragonflies and their relatives are similar in structure to an ancient group, the Meganisoptera, from the 325 Mya Upper Carboniferous of Europe, a group that included the largest insect that ever lived, Meganeuropsis permiana from the Early Permian, with a wingspan around 750 mm (30 in). Evolution The giant Upper Carboniferous dragonfly relative, Meganeura monyi, attained a wingspan around 680 mm (27 in). The infraorder Anisoptera comes from Greek ἄνισος anisos "unequal" and πτερόν pteron "wing" because dragonflies' hindwings are broader than their forewings. Their bright colours and agile flight are admired in the poetry of Lord Tennyson and the prose of H. They are symbols of courage, strength, and happiness in Japan, but seen as sinister in European folklore. They are used in traditional medicine in Japan and China, and caught for food in Indonesia. During mating, the male grasps the female at the back of the head, and the female curls her abdomen under her body to pick up sperm from the male's secondary genitalia at the front of his abdomen, forming the "heart" or "wheel" posture.įossils of very large dragonfly-like insects, sometimes called griffinflies, are found from 325 million years ago (Mya) in Upper Carboniferous rocks these had wingspans up to about 750 mm (30 in), though they were only distant relatives, not true dragonflies.ĭragonflies are represented in human culture on artefacts such as pottery, rock paintings, statues, and Art Nouveau jewellery. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilization, and sperm competition. They are fast, agile fliers capable of highly accurate aerial ambush, sometimes migrating across oceans, and often live near water. In some species, the nymphal stage lasts up to five years, and the adult stage may be as long as 10 weeks, but most species have an adult lifespan in the order of five weeks or less, and some survive for only a few days. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight.ĭragonflies are predatory insects, both in their aquatic nymphal stage (also known as "naiads") and as adults. An adult dragonfly's compound eyes have nearly 24,000 ommatidia each.ĭragonflies can be mistaken for the closely related damselflies, which make up the other odonatan infraorder ( Zygoptera) and are similar in body plan, though usually lighter in build however, the wings of most dragonflies are held flat and away from the body, while damselflies hold their wings folded at rest, along or above the abdomen. Many dragonflies have brilliant iridescent or metallic colours produced by structural colouration, making them conspicuous in flight. Adult dragonflies are characterized by a pair of large, multifaceted, compound eyes, two pairs of strong, transparent wings, sometimes with coloured patches, and an elongated body. ![]() Loss of wetland habitat threatens dragonfly populations around the world. ![]() Most are tropical, with fewer species in temperate regions. About 3,000 extant species of true dragonflies are known. A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |