Examination of the large white and small white butterflies (Pieris spp.) for the presence of mustard oils and mustard oil glycosides

Sinigrin and mustard oils were identified in the pupae of the large white butterfly (Pieris brassicae) and the small white (P. rapae). It is assumed that these substances are sequestered by the larvae from its foodplant and stored. The large white is apparently the more efficient storer of the two, and mustard oils could be detected in the adults, as well as the larvae.