The purpose of the Tischler/Wu experiment was to determine the function of arylphorin in the Manduca sexta, specifically during adult (pharate) development. Two possible functions were thought possible. First was the use of arylphorin as a "reservoir for amino acids" (Tischler and Wu, 1995)--the protein would be broken down to provide amino acids that would be used in the massive restructuring seen during the phartate adult stages (in pupa). The second potential function was the direct use of arylphorin in body structures, specifically the cuticle. This had been seen in Calliphora vicina with the protein calliphorin, a type of arylphorin class protein with high content of aromatic amino acids (Levenbook and Bauer, 1984).
The experiment was conducted by injecting some M.sexta with radiolabeled arylphorin and other insects with radiolabeled phenylalanine for both the middle and late stages of pharate adult development.
The hypothesis was that if arylphorin was, indeed, a storage protein and would be degraded to amino acids that would, in turn, be used in the pharate adult (restructuring before becoming a moth); the insects injected with the radiolabeled arylphorin would show little (significantly) or no difference in distribution of the label into structures in comparision to those insects injected with the labeled phenylalanine. Difference in distribution would indicate the the direct incorporation of arylphorin into tissues. The arylphorin was not broken down into individual amino acids, like phenylalanine, before being utilized.