Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
I haven't had time to come up with a definitive id but those ants are two different species. Winged males and females can be easily differentiated by the size of the head relative to the thorax. When viewed from above a male's head is almost always narrower than the thorax. The head of a female is as wide, or wider, than the thorax.