Developmental changes in the synthesis of haemolymph polypeptides and their sequestration by the prepupal fat body in Calpodes ethlius stöll (Lepidoptera:Hesperiidae)

Abstract

Developmental changes in haemolymph protein and in its synthesis were examined in Calpodes ethlius from late in the fourth stadium to early pupation. The major haemolymph proteins have mol. wts of 470,000, 580,000 and 720,000. Upon dissociation, the 470 K and 580 K proteins each resolve into single polypeptides with mol. wts of 82,000 and 86,000 respectively. The 720 K protein separates into two distinct polypeptides with mol. wts of 86,000 and 90,000. The 82,000 polypeptide is present in the haemolymph at all times but not synthesized either very early in the fifth stadium or after the second critical period. The 86,000 and 90,000 polypeptides are present and synthesized only between the first and second critical periods. Disappearance of the 86,000 and 90,000 polypeptides from C. ethlius haemolymph is correlated with a decrease in haemolymph protein concentration and an increase in fat body protein granules. Injection of [ 14C]-labelled haemolymph proteins into larvae after the second critical period results in the fat body acquiring radioactive polypeptides having M rs of 86,000 and 90,000. These results suggest that the prepupal fat body of C. ethlius sequesters at least one and probably two (the 720 K and 580 K proteins) of the three major fifth stadium haemolymph proteins.