Fig. 7

Adult Dipteran salivary gland cellular architecture. a-b Schematic diagrams of adult female (Ai) and male (b) An. stephensi SG cellular architecture. Cell shape, duct placement, and nuclear positioning are highlighted. Duct chitin (red) is more abundant inside the SG than in the individual duct. Proximal (top) and distal (bottom) are labeled. Insets: Cross-sectional (Aii) and zoom (Aiii) views of An. stephensi SG cells. In Aii, a purple arrow marks the SD, and a green arrow marks the lumen (lu). Individual variation in cellular architecture at many levels was documented in Fig. 3 and Table 4. c Schematic diagram of D. melanogaster SG cellular architecture. Cell shape, the cellular duct, the chitin-rich apical surface of SG cells, and the SG lumen are depicted. Note that nuclear position in Drosophila adult SGs is not as basally biased as in Anopheles stephensi. In An. stephensi, the chitinous duct is a separate structure within the SG, separated from secretory cells by a secretory cavity and a periductal space; in contrast, the Drosophila SG chitin staining is at the apical cell surface, defining the central lumen. In both species, nuclei are smaller and tightly associated with the duct in the ID, but larger and farther from the duct inside the SG. Brown lines denote segments deleted to fit the available space. Female and male Anopheles SGs are approximately to scale. cb: cell body, sc: secretory cavity, bm: basement membrane