The dogbane leaf beetle has a special type of color that shines and changes as the insect changes position or we change position looking at it. This changing color is called iridescence. The beetles' iridescence is produced by special body structures and light. The surface of the body parts of this beetle is made up of stacks of tiny, slanting plates, under which is a pigment (substance that produces color). Some light rays reflect from the surface of the plates, and other light rays reflect from the pigment underneath. At different angles, the light reflects at different speeds, causing interference and resulting in our seeing different colors that shine. See Web Resources section for more information on insect iridescence. The dogbane leaf beetle is a small (8-11 mm.), oblong, shiny insect that displays blue, gold, green, and coppery colors. Its underside is bluish-green. It has wide-set antennae with 11 segments. The larva is white with a brown head. It feeds on roots and leaves of dogbane and other milkweed plants.