Fig. 3.

In vivo localization of PO, RCP, lipids, and polysaccharides in N. monzeni. (A and B) In situ hybridization of PO gene expression (A) and RCP gene expression (B) on abdominal tissue sections of adult insects. PO and RCP genes are preferentially expressed in LGCs in the body cavity of soldier-to-be embryos, whereas neither PO nor RCP is detected in fat body cells in the maternal body cavity. In N. monzeni, when soldier nymphs start growing, LGCs in the body cavity are lost and replaced by fat body cells and ovaries, by which resource allocation from defense to reproduction proceeds. (C) Immunohistochemistry of PO protein on an abdominal tissue section of a soldier nymph. Brownish PO signals are detected in the cytoplasm of LGCs, whereas nuclei are counterstained with hematoxylin in purple. Negative control images corresponding to A–C are shown in SI Appendix, Fig. S4 A–C. (D–G) Transmission EM images of LGCs in an early soldier-to-be embryo (D), a late soldier-to-be embryo (E), a young soldier nymph (F), and a mature soldier nymph (G). (H and I) Immuno-EM images of PO (H) and RCP (I) in LGCs of soldier nymphs. Negative control images corresponding to H and I are shown in SI Appendix, Fig. S4 D and E. (J) Lipid staining of a frozen tissue section of a soldier-to-be embryo with Oil Red, counterstained with hematoxylin in purple. (K) Control staining of an adjacent section without Oil Red. (L) Polysaccharide staining of a sectioned soldier-to-be embryo with periodic acid-Schiff (PAS) reagent in red, counterstained with hematoxylin in purple. (M) Control staining of an adjacent section without PAS. bc, bacteriocyte; br, brain; fb, fat body; gu, gut; hc, hemocoel; ld, lipid droplet; lgc, large globular cell; n, nucleus; tg, thoracic ganglion.