Gynandromorphs

Very occasionally we come across some rather special butterfly specimens. These are gynandromorphs, individuals which are part male and part female. In many species of butterfly males and females have different colour patterns. In these species spectacular gynandromorphs can sometimes arise where one half is male and the other female. The genetic cause of these bilateral gynandromorphs is complex but essentially an X chromosome is lost very early in cell division of the embryo.

The Mocker Swallowtail (Papilio dardanus) showing the female (left), male (right) and gynandromorph (center)

Three specimens of the Common Yellow Glider (Cymothoe egesta). The gynandromorph (center) is slightly asymmetrical as the female half also includes some male cells with the yellow pattern.

Example of a British Brimstone (Gonepteryx rhamni) gynandromorph (center) from the Mark Colvin collection.

Gynandromorphs also occur in other invertebrates, such as this earwig which has one longer male forcep and a short female one.