Dragonflies might rule the skies, but their babies grow up underwater in a larva-eat-larva world. Luckily for them, they have a killer lip that snatches prey, Alien-style, at lightning speed.
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If adult dragonflies are known to be precise hunters, capable of turning on a dime and using their almost-360-degree vision to nab mosquitoes and flies in midair, their dragon-looking babies are even more fearsome.
Dragonflies and damselflies lay their eggs in water. After they hatch, their larvae, also known as nymphs, spend months or years underwater growing wings on their backs.
Without those versatile four wings that adults use to chase down prey, nymphs rely on a mouthpart they shoot out. It’s like a long, hinged arm that they keep folded under their head and it’s eerily similar to the snapping tongue-like protuberance the alien shoots out at Ripley in the sci-fi movie Aliens.
A nymph’s eyesight is almost as precise as an adult dragonfly’s and when they spot something they want to eat, they extrude this mouthpart, called a labium, to engulf, grab, or impale their next meal and draw it back to their mouth. Only dragonfly and damselfly nymphs have this special mouthpart.
“It’s like a built-in spear gun,” said Kathy Biggs, the author of guides to the dragonflies of California and the greater Southwest.
With their labium, nymphs can catch mosquito larvae, worms and even small fish and tadpoles.
“It’s obviously an adaptation to be a predator underwater, where it’s not easy to trap things,” said Dennis Paulson, a dragonfly biologist retired from the University of Puget Sound.
Also known among biologists as a “killer lip,” the labium comes in two versions. There’s the spork-shaped labium that scoops up prey, and a flat one with a pair of pincers on the end that can grab or impale aquatic insects.
-- How many years have dragonflies been around?
Dragonflies have been around for 320 million years, said Ed Jarzembowski, who studies fossil dragonflies at the Nanjing Institute of Geology and Paleontology. That means they were here before the dinosaurs.
-- How big did dragonflies used to be?
Prehistoric dragonflies had a wingspan of 0.7 meters (almost 28 inches). That’s the wingspan of a small hawk today.
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This web site, run by Kathy and David Biggs, has photos and descriptions of California dragonflies and damselflies and information on building a pond to attract the insects to your backyard: bigsnest.member...
The book "A Dazzle of Dragonflies," by Forrest Mitchell and James Lasswell, has good information on dragonfly nymphs.
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21 авг 2024