Dragonflies

Dragonflies are fascinating, with a secret underwater life that most people don't know anything about. The larval stage of a dragonfly lives in a freshwater environment for years as an animal called a nymph. This nymph is a fearsome predator dominating its aquatic environment as a stealthy predator feeding on mosquito larvae, aquatic beetles, midges and water worms, tiny amphipods like scuds, and water snails.

The dragonfly nymph lives entirely under the water’s surface in bodies of water like streams, marshes, and ponds. The juvenile dragonfly uses gills to breathe and can molt (shedding their exoskeleton) between five and 15 times as it grows. Some species spend as much as 5 years in this aqueous form and only a week to a couple of months in the air as dragonflies.

The majority of the insect’s life is spent in the water; sometimes as little as 10 percent of the insect’s total life cycle is spent as an acrobatic stunt pilot. As the nymph undergoes metamorphosis, leaving the water and taking to the air as a dragonfly, only females will return to the water to lay eggs.

This ancient animal comes from a geological time period just before the dinosaurs roamed the Earth 250 million years ago. The early Permian geologic period was a time of giant insects; some scientists speculate that greater oxygen levels (21% higher) helped to support these large creatures. In Kansas, Jurassic-period rock formations contain some of the largest insect fossils found on Earth: a relative of the modern dragonfly, the now-extinct “grifinfly” (Meganeuropsis permiana), which was the size of a large raven or hawk.

Interestingly, dragonflies are sexually dimorphic, similar to many other species of animals, in wich mating pairs are not the same color. Males have much brighter and different colors than the females. Males sport radiant reds and vibrant blues, as well as metallic green, yellow, orange, purple, brown, gray, black, white, and pink! Coloration that develops to attract mates is called nuptial coloration. Male dragonflies also use bright colors to warn rivals away from their prime mating territories.

Female dragonflies appear in duller colors; they avoid predators while they lay hundreds to thousands of eggs in calm freshwater each season. They prefer clean, oxygenated water; dragonflies are a good sign and a true scientific measure of how healthy the bodies of water are around you.

Flight is extraordinary with a dragonfly. The front and rear wings do not move together, which allows for different timing and angles. They have a complete range of motion, being able to fly straight up and down, backward and forward. Like a helicopter, dragonflies can hover easily in midair, then have instant acceleration.

Dragonflies endure g-forces when accelerating and making sharp turns while hunting. They have muscles directly attached to the wing base for better control and speeds measuring up to 36 miles/hours.

Dragonflies have large compound eyes, seeing in a panoramic view of 360 degrees and detecting any small movement. As predators, they have a very high success rate, capturing 95 percent of the prey they target in flight. Lens units called ommatidia facets, which contain 30,000 individual lenses, form a mosaic image for the dragonfly, tracking fast-moving prey. Dragonflies use near-infrared light to spot other dragonflies, use polarized light, and can see ultraviolet light patterns.

Dragonflies come together in great numbers in the late summer and fall, flying over the dunes on Amelia Island. Dragonflies love to chase and eat the late afternoon insects as they gather near the beaches. They like flying low over grassy fields, where their prey also congregate.

Migrating dragonflies use navigational cues, such as ocean shorelines, to orient themselves to fly south to the Gulf of Mexico or Central America. This funnels small insects down a narrow corridor, with the ocean and sand dunes being natural geographic boundaries. It may take the dragonfly several generations to complete a full migration. Dragonflies like to rest on the long blades of sea oats, perfect places for them. Fall on the southern beaches belongs to the dragonflies!

Think about the perfection of a dragonfly.