PROTEINS IN THE HAEMOLYMPH AND OTHER TISSUES OF THE DEVELOPING TOMATO HORNWORM, PROTOPARCE QUINQUEMACULATA HAWORTH

Abstract

The haemolymph proteins of Protoparce quinquemaculata Haworth have been studied by zone electrophoresis in starch gels. Changes in the number of protein bands have been followed from third-instar larvae to the pupal and adult stages. A cycle of change is repeated over the molting period from third to fourth instar and from fourth to fifth instar, and appears to comprise an increase in the number of protein bands in the pharate stage with a decrease immediately after ecdysis. The decrease is not directly associated with the cessation of feeding since starvation does not decrease the blood protein content.The components which make up the main or "common" blood protein have been studied by immunodiffusion techniques. Two antigens appear to contribute to this complex and these are present consistently through larval and pupal life, but both are absent in the adult and egg. The possibility is considered that these components may be significant in the molting cycle.Comparisons have been made between the protein patterns of the blood and those of other tissues at similar stages in development. The electropherograms indicate that some blood proteins become located in the fat body during the pupal stage and are added to at adult emergence. A blue-green pigment becomes dissociated from the protein with which it migrated in larval electropherograms, and becomes located in the ventral fat body of pupae. A distinctly sex-specific protein was not observed in this insect and the matter of sexual dimorphism in blood proteins is discussed.