Figure 2
From: Circadian rhythm of glycoprotein secretion in the vas deferens of the moth, Spodoptera littoralis
Circadian rhythm of secretory activity in the UVD of S. littoralis Longitudinal sections of the UVD showing time-dependent accumulation of PAS positive granules in apical cytoplasm of epithelial cells in LD (a), DD (b), and LL (c). The levels of PAS-positive granules (arrows) show daily oscillations in LD and DD conditions with high accumulation occurring at night. In LL, intermediate levels of PAS-positive material are present at all times. The experiment was performed on 8–10 males per time point in each photo regime with similar results. White and black horizontal bars indicate periods of light and darkness, respectively.