Blue Dasher

Common name: Blue Dasher, Fishers Island, NY, July 2017

Scientific name: Pachydiplax longipennis 

Not a moth, but too beautiful to omit. The blue dasher is one of the more common dragonflies in the eastern U.S. and one of the most striking. Like many dragonflies, this species is sexually dimorphic, meaning that the appearance of the individual depends on its gender. Only males develop bright blue abdomens, whereas females have an orange-and-black pattern instead. This is a fully mature male.

When adults perch, they tend to raise their abdomens in the air in what is known as the “obelisk” position. This is believed to be an effective way to minimize heat by allowing more wind to pass over the abdomen.