Distribution of C3 to C6 sNPF receptor immunolabeled clusters observed in the anterior queen brain. A: Merged confocal image of pictures obtained with red (receptor signal) and cyan (DAPI nuclear staining) channels. B: Image obtained with red channel. In A and B, the cluster C3 (arrow) includes a group of eight cells (B, dashed circles) located on each side of the superior protocerebrum (sP) near the lateral calyces (lCa). C: A schematic shows the relative position of clusters C3 to C6 in the brain. D-H: Whole mount images obtained with Axioimager A1 microscope (nuclei stained in blue with DAPI). D: The cluster C4 includes six cells distributed vertically in the protocerebrum (P). E: The anterior brain view shows the relative position of clusters C4 and C5 (arrows) on each side of the protocerebrum, and the cluster C6 (arrowhead) on the inferior medial protocerebrum (imP). mP, medial protocerebrum; iP, inferior protocerebrum (iP); ALo, antennal lobe. F: A higher magnification image of E showing that the cluster C5 contains three cells horizontally aligned on the superior edge of the antennal lobe which is nearby the inferior protocerebrum. Confocal images G and H: G, merged of red and cyan channels and H, a red channel image. The cluster C6 includes a group of about 30 cells (arrowheads) located at the edge of the inferior medial protocerebrum above the esophageal foramen (G, white solid line). Thickness of stacked confocal images: 8.20 μm for A and B; 18 μm for G and H.