Genetics of a "zebra" pigment mutation in the larvae of Danaus plexippus, L. (Nymphalidae: Danainae)

We report a mutation in monarch butterflies that results in a lack of yellow pigment in larvae, pupae and eggs. Genetic studies reveal that this phenotype is caused by a recessive autosomal allele with normal Mendelian segregation. We did not detect an effect on butterfly size or asymmetry, but mutant individuals of both sexes appear to suffer lower reproductive success than normal individuals. We hypothesize that the mutants are unable to sequester carotenoids from their larval host plants.