That little thing on top of the Rudbeckia head is a caterpillar decorated with bits of vegetation! These very small caterpillars will chew off bits of petals and adorn their body with them. With each new instar (moult), the caterpillar has to replace the bits of vegetation. The idea of course, is to protect itself from predators by pretending to be part of the plant. I think this may be the only caterpillar in our area that does this sort of thing. As an adult (moth), it is a beautiful emerald green, called the Wavy-lined Emerald.