The Inheritance of Cuticular Coloration in the Tobacco Horn worm (Lepidoptera: Sphingidae)

Laboratory colonies of white and black color-strains of the tobacco hornworm, Manduca sexta (L.) were used to study the inheritance of cuticular coloration where color is under the control of genes located on separate chromosomes. The white and black color traits are inherited as autosomal recessive and sex-linked recessive traits, respectively. Because the genes for these traits are located on separate chromosomes, the tobacco hornworm system may serve as a model for investigating the interactions between genes. Coloration of progeny of crosses between individuals from the white and black laboratory colonies, F₁ self crosses, F₁ reciprocal crosses and F₁ backcrosses was examined to determine the inheritance of these two traits and potential epistasis between them. Genetic analysis showed that the two color traits are inherited independently and result in a brown phenotype in the double homozygous, recessive condition.