The Egyptian scarab specifically represents luck in the form of solar power. The sun was a big deal to ancient Egyptians, with the ability to yield bumper crops, or bear down so brightly as to blight growth entirely. Scarabs utilize the power of the sun by rolling up their eggs in mud or dung. The hot sun bakes the little mud balls - essentially incubating their eggs. Pretty resourceful way to hatch babies. And so, not only is the scarab lucky because of its own ingenuity, it's also symbolic of rebirthing into a new dawn of life.
