With over 158,000 described species, flies (the insect order Diptera), are among the most diverse groups of living organisms on the planet.

This diversity transcends simple species numbers and is demonstrated in the great breadth of morphological, ecological, and behavioral variation found in the group.

Flies have a deep evolutionary history that extends back to the Permian Period, over 250 million years ago.

The FLYTREE project is an international research collaboration funded by the US National Science Foundation, to elaborate and discover the details of fly relationships and diversity with the ultimate goal of providing a newly resolved phylogeny for this major branch of the Tree of Life.