Fruit flies draw a bowl of ripe fruit from above

I have been interested in the cumulative paths of insects like fruit flies and have been developing a methods for visualizing all the routs taken. In the instances where I have done this I am amazed to find how much of the surface the flies cover. Dotted lines are the flights of the flies. The big black blobs are a house fly passing through the scene. The dark and jagged lines are the fruit flies walking.