for a few years I fished some "sandhill" lakes in the Florida panhandle which had tremendous hatches of Hexagenia mayflies in spring. When the hatch was going full swing, the big bluegills became EXTREMELY selective, feeding on emergers-- to the point that the locals stopped fishing for them because all anyone used was poppers, and during the hatch time they just didn't hit poppers. I absolutely killed them on big size 6 foam-wing emergers.