Larval Hemolymph Protein Patterns in Tobacco Hornworms1 Parasitized by Apanteles congregatus23

Abstract

Quantitative changes in hemolymph proteins from each physiological phase of the last 3 larval instars of the tobacco hornworm, Manduca sexta (L.), parasitized by the gregarious parasitoid, Apanteles congregatus (Say), were studied by means of acrylamide gel electrophoresis. Six of the 10 observed anodical migrating protein bands occurred in all phases and instars. Total protein concentration was lowest in phase I of the 3rd and 4th instars and increased to a maximum in phase IV. Total protein also was low in phase I, 5th instar; however, levels increased only in phase II, then decreased in phases III and IV. Concentrations of mucoproteins, polysaccharides and phospholipids, associated with certain bands, were much reduced in parasitized larvae. Sterol-protein complexes were found in the hemolymph of certain aged unparasitized larvae but not in parasitized larvae. Gas chromatographic analysis demonstrated reduction of hemolymph sterols by at least a factor of 10³ in parasitized larvae.