Below is a dragonfly nymph from the area of the first stream Fred and I sampled. This one was in a vernal pool close by the stream, the nymph is about three quarters of an inch long. When I first took the photo I didn't notice the small shrimp like critter clinging to the tail of the nymph. The camera revealed something that otherwise would have been overlooked.

Because the dragonfly is a voracious predator this hitchhiker may figure that clinging to the nymphs tail is the best way to keep out of its mouth.  If we could increase the magnification of this photo we would likely find a smaller critter hitchhiking on this shrimp like critter, and a smaller one clinging to that one, and so on and so forth.

If we were to expand the scope of this photo to include the whole pool we might find a frog munching on an unwary nymph. If we were to expand it even further we might find the unwary frog getting munched by a snake. Upon widening the scope of our photo even further, we find the unwary snake has fallen victim to the hawk.  Each creature dependant on one another, for survival.