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Dragonflies having simple flaps shed the eggs in water, mostly in flight. Dragonflies having ovipositors use them to puncture soft tissues of plants and place the eggs singly in each puncture they make. [32] [34] [35] [36] Dragonfly nymphs vary in form with species, and are loosely classed into claspers, sprawlers, hiders, and burrowers. [17]
At high angles of attack, the flow separates over the leading edge, but reattaches before reaching the trailing edge. Within this bubble of separated flow is a vortex. Because the angle of attack is so high, a lot of momentum is transferred downward into the flow. These two features create a large amount of lift force as well as some additional ...
The green darner is a large dragonfly; males grow to 76 mm (3.0 in) in length with a wingspan up to 80 mm (3.1 in). [9] [10] Females oviposit in aquatic vegetation, eggs laid beneath the water surface. Nymphs (naiads) are aquatic carnivores, feeding on insects, tadpoles, and small fish.
They frequently fly high up into the sky in search of prey, which includes butterflies, other odonata and tadpoles. If their hunt is successful, they eat their smaller prey while flying. The dragonflies breed in a variety of aquatic habitats from large ponds to dikes and slow-moving rivers, but require a plentiful supply of vegetation in the water.
They are very conspicuous dragonflies; seen in swarms over paddy fields, playgrounds or open areas. They fly tirelessly with typical wandering flight for hours without making any perch. [8] Their flight speed is up to 5 m/s. [20] Especially in the autumn, the wandering glider flies in large swarms, using thermals to advantage.
The insect family Macromiidae contains the dragonfly species known as cruisers or skimmers.They tend to fly over bodies of water (and roads) straight down the middle. They are similar to Aeshnidae in size, but the eyes are green and just barely meet at the top of the head.
Their flight is very fast as they dart and dive above the water. They are very territorial and will fight with rival males and any other dragonflies they happen to encounter. They characteristically return to a favoured perch, in the sun. When a female enters a male's territory the male will fly up and grab the female.
Common worldwide or nearly worldwide genera are Aeshna and Anax. Anax includes some of the largest dragonflies, including the North American A. walsinghami, Hawaiian A. strenuus, European A. imperator and A. immaculifrons, and African A. tristis, but these are all exceeded by another member of the family, the Asian Tetracanthagyna plagiata, which by wingspan and weight is the world's largest ...