Abstract: 【Aim】 This study aims to identify the neuropil structure of the brain of male adult of Heliothis virescens, to reconstruct and print the three-dimensional brain models, and to use the established 3D printing protocol to print the brain models of Drosophila melanogaster, Apis mellifera and Schistocerca gregaria. 【Methods】 Immunohistochemical staining with a synaptic protein antibody was used to label the neuropil structures of H. virescens brain. The brain images were obtained by using a confocal laser scanning microscope, and the three-dimensional brain models were created by using imaging software and printed by using a 3D printer. 【Results】 The brain of male adult of H. virescens and its main neuropils including gnathal ganglion, antennal lobes, optic lobes, anterior optic tubercle, central body, and mushroom bodies were identified, and the digitalized three-dimensional brain models were created. For the first time, the three-dimensional brain models of male adult of H. virescens were printed by using a 3D printer and the digitalized models were transformed to the physical and solid models. Based on both digital and printed brain models of H.virescens and other three insects (D. melanogaster, A. mellifera and S. gregaria), the brain neuropils for the gustatory center, olfactory center, visual center, and the center for memory and learning were compared between these insect species. 【Conclusion】 The printed brain models offer a new form of brain visualization. The physical and solid insect brain models can be printed in desired size and be handled in hands for the visualization from any angles. The printed brain models facilitate the identification of neuropils and their spatial relationships, and the comparison for the equivalent structures in different insect species.

Key words: Insect, brain, neuropil, antennal lobe, optic lobe, mushroom body, gnathal ganglion, three-dimensional model, 3D printing