The underwing of the marbled white is much paler, almost a gray version of the upper. Both sexes are similar in pattern but males are a purer white. Females are slightly creamy in appearance, and are marked in brown rather than the black of males. The pattern of the marbled white is easily remembered by insectivorous birds, and is probably a form of aposematic coloration, functioning to advertise the toxic nature of the butterfly.
The photograph of this beautiful butterfly was captured in the nature reserve ‘Kiesgrube Käppelin’ close to Weil am Rhein in Germany.