What happened to the leaf? Monarchs do a curious thing. They chew a notch in the stalk of a leaf before they eat it. This behavior is called "leaf-notching."

Why would a monarch cut the very leaf it is standing upon, until it dangles like a loose tooth? Because milkweed contains a sticky, white juice called latex. Leaf-notching cuts off the supply of latex to the leaves. This makes milkweed safe for the monarch to eat.