Light microscopic images of representative ovaries were taken from untreated (A), RNAi-Fluc (B), and RNAi-EOF1 (C). Mosquitoes were dissected at 36 h PBM, and dissected live ovaries were incubated with a caspase inhibitor (red), fixed with 4% paraformaldehyde, and stained with phalloidin (green). Confocal images of the corresponding ovaries were taken from untreated (D), RNAi-Fluc (E), and RNAi-EOF1 (F) mosquitoes. Scale bar for the images (A–F) is 100 μm. A high degree of caspase-mediated apoptosis was observed in the follicles of ovaries from RNAi-EOF1 females, possibly resulting in the lower fecundity as shown in Fig 1F. DIC (G) and confocal (H) images of ovaries from RNAi-EOF1 mosquitoes are taken at a higher magnification (scale bar: 50 μm). Caspase activity was more restricted to the oocytes, rather than in the follicular epithelial cells. Images (A–H) were collected with a spinning disk confocal microscope. Ovaries from 10–15 individual mosquitoes from each group were analyzed. DIC, differential interference contrast; EOF1, eggshell organizing factor 1; Fluc, firefly luciferase; PBM, post-blood meal; RNAi, RNA interference.