The Sky Fly
The sky fly, Muscus caelum, also called the blue fly, is commonly seen as the most beautiful species of fly in the world. Its intense azure coloration, a result of both pigments, as well as light refraction caused by nanostructure in the fly's cuticule (exoskeleton), regularly takes one of the top spots in the yearly publication of the most striking colors. Sky flies, contrary to what their name might lead you to believe, do not live in the air. In fact, they are the only species of fly to live in the water.
Blue flies survive mostly off of fish excrement, much as their airborn cousins are attracted to animal excrements. Sky flies most often either follow schools of fish, or lurk around rich habitats, such as coral reefs, where many marine animals pass to breed or feed. Their irridescent color is an adaptation to their aquatic environment, and, seen from the water, their sparkling passes for just another reflection of sunlight.
In recent years, sky fly populations have suffered from the rapid degradation of the oceans. Both the decline in fish populations, as well as the destruction of marine habitats, through increased acidity of the seas as well as direct human intervention, has seen their numbers dwindle, and in many places where it was common to see the sparkling flashes of brightest blue when one went diving, the sea has gone dark. In addition, sky flies have become a popular centerpiece for jewels, which has further accelerated their decline. But their dissappearance does not only affect the animal world.
The sky flies have long been used by a number of people to ascertain the state fo the sea. When to go fishing, which were the best spots, when and how the weather might change, the sky flies have been a useful indicator of the state of the seas, and intense scientific studies by Dr. Rupert Seastone's group at the Institute for Aquatic Insects of Melbourne (IAI) has shown that they were indeed an accurate proxy for these events. Their dwindling numbers have made it hard for the people to judge the waters, and there has been an increase in shipwrecks, as well as victims of storms, in many native populations that are dependant on the sea. Some even go so far as to say that the decline of the sky fly will lead to the death of the seas themselves. Western science sees things the other way around, but there is no denying that both events are connected.