|
Obelisk Posture
The obelisk posture is a handstand-like position that some dragonflies and damselflies assume to prevent overheating on sunny days. The abdomen is raised until its tip points at the sun, minimizing the surface area exposed to solar radiation. When the sun is close to directly overhead, the vertical alignment of the insect's body suggests an obelisk. Function and occurrence Dragonflies may also raise their abdomens for other reasons. For instance, male Blue Dashers (''Pachydiplax longipennis'') assume an obelisk-like posture while guarding their territories or during conflicts with other males, displaying the blue pruinescence on their abdomens to best advantage.Corbet, 285-287.Clifford, 192-193. However, both females and males will raise their abdomens at high temperature and lower them again if shaded. This behavior can be demonstrated in the laboratory by heating captive Blue Dashers with a 250 watt lamp, and has been shown to be effective in stopping or slowing the rise in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handstand
__NOTOC__ A handstand is the act of supporting the body in a stable, inverted vertical position by balancing on the hands. In a basic handstand, the body is held straight with arms and legs fully extended, with hands spaced approximately shoulder-width apart and the legs together. There are many variations of handstands, all of which require the performer to possess adequate balance and upper body strength. Kinematics Handstands use the wrist flexor muscles as well as the anterior deltoid, pectoralis major, latissimus dorsi, biceps brachii, and trapezius descendens. It is considered demanding in terms of both the muscle and joint requirement. According to a 2017 study most handbalancers use wrist movement to maintain balance in a handstand. Another study found that handbalancers who were also expert gymnasts had better coordination than those at an intermediate level of gymnastics. More advanced practitioners also altered their center of pressure less to change the center of mas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gomphidae
The Gomphidae are a family of dragonflies commonly referred to as clubtails or club-tailed dragonflies. The family contains about 90 genera and 900 species found across North and South America, Europe, Asia, and Australia. The name refers to the club-like widening of the end of the abdomen (abdominal segments 7 through 9). However, this club is usually less pronounced in females and is entirely absent in some species. Etymology The name may be derived from Latin ''gomphus'' or ''gond'' meaning "hinge". Characteristics Clubtails have small, widely separated compound eyes, a trait they share with the Petaluridae and with damselflies. The eyes are blue, turquoise, or green. The thorax in most species is pale with dark stripes, and the pattern of the stripes is often diagnostic. They lack the bright metallic colors of many dragonfly groups and are mostly cryptically colored to avoid detection and little difference between the sexes is seen. Adults are usually from in length; there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the creature's body, each of which is in turn composed of multiple segments. The human thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures. Many diseases may affect the chest, and one of the most common symptoms is chest pain. Etymology The word thorax comes from the Greek θώραξ ''thorax'' "breastplate, cuirass, corslet" via la, thorax. Plural: ''thoraces'' or ''thoraxes''. Human thorax Structure In humans and other hominids, the thorax is the chest region of the body between the neck and the abdomen, along with its internal organs and other contents. It is mostly protected and supported by the rib cage, spi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tramea
''Tramea'' is a genus of dragonflies in the family Libellulidae, the skimmers and perchers. Species of ''Tramea'' are found in tropical and subtropical regions around the globe. They typically have colored bases to their otherwise translucent hindwings. In particular when they fly, this creates the impression of their carrying bags at the start of their abdomens. They are known commonly as saddlebags or saddlebags gliders. Species The genus ''Tramea'' includes the following species, some of which have subspecies: *'' Tramea abdominalis'' – Vermilion Saddlebags *''Tramea aquila'' *''Tramea basilaris'' – Keyhole Glider, Wheeling Glider, Red Marsh Trotter ** ''Tramea basilaris burmeisteri'' *'' Tramea binotata'' – Sooty Saddlebags *'' Tramea calverti'' – Striped Saddlebags *'' Tramea carolina'' – Carolina Saddlebags *''Tramea cophysa'' *''Tramea eurybia'' **''Tramea eurybia monticola'' *''Tramea insularis'' – Antillean Saddlebags *'' Tramea lacerata'' – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dragonhunter
The dragonhunter (''Hagenius brevistylus'') is a clubtail dragonfly of the eastern United States and southeastern Canada. The dragonfly is much larger than any other North American clubtail, at , with black and yellow markings and green eyes. Males can be distinguished at a distance by their habit of curling their abdomens under while flying, forming a sideways J shape. The dragonhunter is the only member of genus ''Hagenius''. Its closest relatives are Asian dragonflies of genus ''Sieboldius'', which are also sometimes called "dragonhunters". Together, the two genera form the subfamily Hageniinae. The nymph is unusual, with a very flat, wide body. It is slow-moving and lives among bark and leaf litter at the edges of streams, where its dark color provides camouflage. The adult feeds on large insects, including darner and clubtail dragonflies, sometimes ambushing them from above. It also takes monarch butterflies, eating the thorax and abdomen first to avoid the greatest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odonata 001 Contrast Adjusted
Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, though members of their total group, Odonatoptera, first appeared in Late Carboniferous. The two common groups are distinguished with dragonflies, placed in the suborder Epiprocta, usually being larger, with eyes together and wings up or out at rest, while damselflies, suborder Zygoptera, are usually smaller with eyes placed apart and wings along body at rest. All Odonata have aquatic larvae called naiads (nymphs), and all of them, larvae and adults, are carnivorous. The adults can land, but rarely walk. Their legs are specialised for catching prey. They are almost entirely insectivorous. Etymology and terminology Fabricius coined the term ''Odonata'' in 1793 from the Ancient Greek ( Ionic form of ) 'tooth'. One hypothesis is that it was because their maxillae are notably toothed. Most insects also have toothed mandibles. The wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoregulate
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation. The internal thermoregulation process is one aspect of homeostasis: a state of dynamic stability in an organism's internal conditions, maintained far from thermal equilibrium with its environment (the study of such processes in zoology has been called physiological ecology). If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. Humans may also experience lethal hyperthermia when the wet bulb temperature is sustained above for six hours. The opposite condition, when body temperature decreases below normal levels, is known as hypothermia. It results when the homeostatic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libellulidae
The skimmers or perchers and their relatives form the Libellulidae, the largest dragonfly family in the world. It is sometimes considered to contain the Corduliidae as the subfamily Corduliinae and the Macromiidae as the subfamily Macromiinae. Even if these are excluded (as Silsby does), there remains a family of over 1000 species. With nearly worldwide distribution, these are almost certainly the most often seen of all dragonflies. The genus ''Libellula'' is mostly New World, but also has one of the few endangered odonates from Japan: ''Libellula angelina''. Many of the members of this genus are brightly colored or have banded wings. The related genus ''Plathemis'' includes the whitetails. The genus ''Celithemis'' contains several brightly marked species in the southern United States. Members of the genus ''Sympetrum'' are called darters (or meadowhawks in North America) and are found throughout most of the world, except Australia. Several Southern Hemisphere species in the gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calopterygidae
The Calopterygidae are a family of damselflies, in the suborder Zygoptera. They are commonly known as the broad-winged damselflies, demoiselles, or jewelwings. These rather large damselflies have wingspans of 50–80 mm (compared to about 44 mm in the common bluetail damselfly, '' Ischnura elegans''), are often metallic-coloured, and can be differentiated from other damselflies by the broader connection between the wings and the body, as opposed to the abrupt narrowing seen in other damselfly families. The family contains some 150 species. The Calopterygidae are found on every continent except Antarctica. They live along rivers and streams.Córdoba-Aguilar, A. & Cordero-Rivera, A. (2005)Evolution and ecology of Calopterygidae (Zygoptera: Odonata): status of knowledge and research perspectives.''Neotrop. Entomol'' 34(6), 861-879. Etymology The name is derived from Greek ''kalos'' meaning beautiful and ''ptery'' meaning winged. Characteristics The adults have metallic bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dragonflies
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threatens dragonfly populations around the world. 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. Many dragonflies have brilliant iridescent or metallic colours produced by structural colouration, making them conspicuous in flight. An adult dragonfly's compound eyes have nearly 24,000 ommatidia each. Dragonflies 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celithemis Eponina
The Halloween pennant (''Celithemis eponina'') is a species of dragonfly in the family Libellulidae. It is native to eastern North America, including Ontario in Canada and the United States as far west as Colorado.NatureServe. 2015''Celithemis eponina''.NatureServe Explorer. Version 7.1. Accessed February 9, 2016. Description The Halloween pennant has been described as looking very similar to a butterfly. Its wings are entirely orange-yellow in color with dark brown bands, the Halloween inspiration for its common name. Dragonflies of its genus perch at the tips of plants, waving in the breeze like pennants. The young has yellow markings, including a stripe on its back. The adult male and female may develop pale red markings, especially on the face. This species is about 38 to 42 millimetres long. It is orange. Distribution and habitat This species occurs in eastern North America. In the southern part of its range it is in season all year round. In northern latitudes it can be see ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_male.jpg "Click for more on -> Calopterygidae")
