Coloration and pteridine pattern in a new, yolk body mutant of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

A yolk body (yb) trait is the sixth body-colour mutation, discovered in P. apterus, affecting the pteridine biosynthesis. It causes a yolk-like coloration of the mutant body, except the eyes which remain red-pigmented, similarly as in wild-type bugs. While the yb homozygous nymphs and very young imagoes are characterized by yolk-pigmentation of epidermal cells, the body, particularly the forewings of older homozygous mutant adults, turn to yolk-orange colour and then become brick-red. The yb trait exhibits complete penetrance and uniform expression in both sexes. Eight different pteridines have been identified in the yb mutant nymphs and imagoes with use of the paper and thin-layer chromatography. Developmental aspects of the changes in pteridine content found in both studied traits are discussed.