Echinacea Eatery, Part 2: Pearl Crescent on Echinacea Leaf

Unlike the Silvery Checkerspot in Echinacea Eatery, Part 1, this Pearl Crescent is not feeding.  Instead, it is rhythmically flapping its wings:

Pearl Crescent on Echinacea Leaf

Riparian Buffer, Creek Field Prairie Restoration

July 19, 2019

Perhaps it is thermoregulating, as it was a very hot day.  Or maybe it is creating air currents to waft pheromones into the world.  Or maybe it is simply exercising its wing muscles, keeping limber.  Or perhaps is is indicating to potential predators that striking would be a waste of their energy, as this butterfly is ready to fly.

Maybe the reason is some combination of the above.  

According to Photographic Field Guide to the Butterflies of the Kansas City Region, by Betsy Betros, the one pictured here is a female, due to the pale knob on the end of the antenna.