The Blug: Dragonflies
The acrobatic aerial assassin
M.K. Manoylov • August 10, 2020
Dragonflies don't fold their wings back at rest — the continue to stick straight out like airplane wings. [MK Manoylov | CC BY-NC-ND 2.0]
Ever try to catch a dragonfly? It’s extremely difficult. Who would have thought that living for 300 million years on this planet would make them good at survival.
Why are dragonflies so darn evasive? Dragonflies are some of the few insect families that catch prey midair. They eat other flying insects, so they need to be especially quick and agile during flight.
Dragonflies can fly vertically and hover like a helicopter. Dragonflies are so good at catching prey that they can catch 95% of prey in an enclosure, according to a Harvard Study. So there’s no way slow humans like us can catch a dragonfly with our bare hands.
Does their eyesight also have something to do with their hunting ability? Dragonflies appear to have those two massive compound eyes for a reason. A compound eye has thousands of tiny visual units in them — you’ve seen them before on flies and bees.
A closeup of a dragonfly’s eyes. [Credit: Michael Payne | CC-BY-SA-3.0]
A dragonfly’s retina contains thousands of photoreceptors to create a panoramic view of their surroundings. Parts of their eyes help them spot prey against a bright sky, and other parts use UV light to give them a view of the world humans can barely imagine.
I heard that dragonflies used to be massive. Is that true? Correct! The dragonfly’s ancestors used to be about the size of birds or even a house cat, it seems.
Here’s why: Dragonflies breathe spiracles, or tiny holes, throughout their body. Oxygen diffuses throughout their body and nourishes their cells, keeping them alive.
There was a lot more oxygen in the atmosphere millions of years ago. Scientists think that dragonflies and other bugs were huge millions of years ago to avoid oxygen poisoning.
I don’t know about you, but I think seagull-sized dragonflies would be pretty cool.
Dragonfly fun facts:
- The average lifespan of a dragonfly is six months.
- Dragonflies are easily confused with damselflies. Both insects are in the same taxonomic order, but damselflies have thinner bodies and fold their wings back when at rest. A dragonfly’s wings stick straight out.
- There are over 5,000 species of dragonflies.
- Dragonflies have three stages in their life cycle — egg, nymph, and adult. The first two occur underwater.