Influence of exogenous 20 (20E) on the hyperproteinemia-induced delay of fat body (FB) remodeling. (A) Typical histomorphology of the FB during larval–pupal metamorphosis. SRd, start of FB remodeling. Rd, FB remodeling. (B) Timeline of paurometabolic development from the wandering stage to the adult stage. The plasma protein concentration (PPC) throughout development, as shown in Figure 1B. Each hemolymph sample for surveying PPC consisted of an equal volume of hemolymph from three individual silkworms and was measured three times (n = 3). (C,D) Silkworm metamorphosis. Indices of development expressed in terms of the pupation, semi-pupa, and larval rates in the CK (n = 32 individuals), AM (n = 50 individuals) and AM+20E (n = 50 individuals) groups. CK, the control group; AM, animal model of hyperproteinemia in which hyperproteinemia was induced at the wandering stage; AM+20E, the larvae of the AM were saved by injecting individual larvae with 4 μg of 20E 24 h after the induction of hyperproteinemia; W, the wandering stage; S, the spinning stage; PP, the pre-pupal stage; P, the pupal stage; A, the adult stage; SP, the semi-pupa stage. L, the larval stage before the pre-pupal stage. Bars are 50 μm and 1 cm in (A,D), respectively. To observe the morphology of the silkworm, the cocoon shells in the CK group were peeled off every 12 h until 48 h after spinning. This treatment also ensured the consistency of the micro-environment among the silkworms that spun their cocoons in the CK group and those that did not in the AM and AM+20E groups.