When you think of butterflies, more than likely you imagine flying insects with brightly coloured wings. The patterns found on the wings vary from species to species, however, in all cases they are symmetrical. Typically, the male and female butterfly of a species have different colouring, much like you would see in birds. Most butterflies have different colouring on either side of their wings. The facing side (recto) tends to be the more vibrant of the two sides, used to warn predators that they are poisonous. When in danger they fold up their wings and hide behind their duller side (verso) which provides camouflage.
Although it is very rare, a single butterfly can be half female and half male. This condition is known as gynandromorphy – where cells fail to split their sex chromosomes during development. This results in a butterfly that is literally one half male colouring and one half female colouring. This phenomena occurs mostly in the insect world but also affects birds and crustaceans. Shown here is the Eastern Tiger Swallowtail butterfly – the yellow side is male and the darker side is female.