African Blue-Banded Swallowtail

In this species, as well as in many others of the same genus, males exhibit a much darker black than females. A microscopic view of the scales revealed that, in males, the black scales are covered in holes, like a sponge.
This fact makes the scales less reflective and more light absorbent, which makes them appear blacker. As a result, the blue bands of the males are more noticeable than those
of the females. Also, unlike females, males exhibit a golden band on the underside of the wings.