Because these insects require stable oxygen levels and clean water, scientists consider them reliable bioindicators of the health of an ecosystem. Disappearing fliersĭragonflies are important to their environments both as predators (particularly of mosquitos) and as prey to birds and fish. ( Sometimes they will mate in the air.) Mating takes just a few seconds, after which the female can immediately lay her eggs. When they land, the female curls her abdomen under to meet his secondary genitalia, forming a “mating wheel” that can resemble the shape of a heart. When he finds a receptive female, he grasps her behind her head with claspers at the tip of his abdomen, and the two fly off together. First the male goes through what’s called self-insemination, curling his body to transfer sperm from his primary genitalia, at the tip of his abdomen, to the secondary genitalia, just below the thorax. Mating wheelĪdults also look for opportunities to mate. Their arms slant upward, forming a type of basket and enabling them to scoop up prey in flight. Adults live only about a month, hunting flies, mosquitos, and midges. They undergo between six and 15 molts before emerging as fully formed adult dragonflies, a process that takes about 12 hours. Nymphs propel themselves quickly by sucking water into their abdomen and then spitting it out.
They may even cannibalize other dragonfly nymphs. Called naiads or nymphs, these larvae stay in the water for up to three years, hunting aquatic insects, mosquito larvae, or small fish with a lower jaw that reaches out and opens up sideways, snatching prey into their mouths. Around midsummer, females hover over bodies of fresh water and dip in their abdomens, laying eggs that hatch in about seven to eight days. Watery beginningsĭragonflies begin their lives in the water. Their compound eyes are so large they nearly touch, and each one has about 28,000 single eyes, or ommatidia.Īround 7,000 species of true dragonflies are alive today, and, together with the closely related damselflies, they form the group Odonta, which goes back 325 million years. Dragonflies can reach speeds of up to 35 miles an hour and fly just as gracefully backward by lifting off vertically, helicopter style.
Are dragonflies apex predators zip#
Living on every continent but Antarctica, these insects are instantly recognizable by their large bodies four long, horizontal wings and the way they hover and zip around. Whether delicately perched on a cattail or hovering over a pond, dragonflies are a sure sign of summer. Current Population Trend: Decreasing What is a dragonfly?
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