One of my favorite museum exhibits is the round ceiling tank at the Monterey Bay aquarium, where a huge school of silver-colored fish swim in an endless circle. It is hypnotic, fascinating, and strangely calming.
Watching flies in a mating swarm can be that way too. Usually, it is a group of male flies we see, all jockeying for the best position in the air. Presumably, this allows arriving females to recognize those that are superior and choose the male in the “best” position for the one with which they will mate.
Thinking of the Monterey Bay experience, I wanted to document a fly mating swarm, and finally got the chance this summer. A group of empid flies (also known as “dance flies”) were flying in a brilliant shaft of light against a dark conifer background, perfect for my purposes. Let me know what you think of the result!