The vitellogenin of the ring-legged earwig,Euborellia annulipes(Lucas) (Insecta: Dermaptera)

Abstract

Using Polyacrylamide gel electrophoresis, labelling procedures and immunological methods, an extraovarian synthesis of vitellogenin has been demonstrated in Euborellia annulipes. Electropherograms of the haemolymph of 1-wk-old mated females show an extra protein fraction on the second day after mating; the concentration of this fraction in the haemolymph falls from the fifth day after mating. The fatbody incorporates [3H]leucine into the proteins synthesised by it during the period of oocyte formation. The proteins extracted from the fatbody and ovary of females of the first reproductive cycle show a high level of radioactivity 3 days after mating, suggesting a simultaneous release of proteins from the fatbody and uptake by the oocytes. On the other hand, TCA-precipitable fractions of the ovary, obtained from females on the pre-ovipositional day, record a high [3H]activity but similar fractions from the fatbody only show minimum radioactivity. Antibodies prepared against the antigens obtained from the crude yolk extract reacted with the proteins from the haemolymph and also with the proteins from fatbody extracts of females of the first reproductive cycle.