This dragonfly doesn’t perch like this for fun. His pose is a threat display.
This is a male Common Whitetail (Plathemis lydia), a showy dragonfly with a white pruinose abdomen and clear black-striped wings.
Common Whitetail males are highly territorial. They live near ponds, marshes and slow moving rivers where they defend 10 to 30 yards of the water’s edge and conspicuously chase away all other males. When they’re not chasing or fighting they pose like this to let rivals know they mean business.
Their white pruinose backs are the warning sign. Pruinose refers to the dusty, frosted appearance caused by a pigment that covers the insect’s “skin.” In nature, pale-colored pruinescence often reflects ultraviolet light. Perhaps this bug glows in sunlight. I wish I could see it!
Female Common Whitetails look quite different because their tails aren’t white, a feature that probably protects them from male aggression.
Look for males patrolling and chasing at the water’s edge. Find females nearby, choosing mates and looking for places to lay their eggs.
These dragonflies are good bugs to have around. They eat mosquitoes.
(photo of male by Chuck Tague, photo of female from Wikimedia Commons; click on the image to see the original)