Glomerular identification in the antennal lobe of the male moth Helicoverpa armigera.

This study investigates anatomical organization of the antennal lobe (AL) glomeruli of the male cotton bollworm Helicoverpa armigera by synaptic antibody staining combined with three-dimensional reconstruction. To identify all glomeruli, their boundaries were accurately determined by means of several additional staining techniques visualizing the neuron categories forming the characteristic spherical neuropils. In total, 78-80 glomeruli were identified in the male H. armigera. The number of glomeruli was considerably larger than that previously reported in this species. Thus, compared with previous studies, we identified 15 new glomeruli, G63-G77. Most of them are located in the posterior part of the AL, which was previously considered to be a part of the protocerebrum. From the general anatomical organization of the AL glomeruli of H. armigera, we classified these neuropil structures into four groups, the macroglomerular complex, posterior complex, labial-palp pit organ glomerulus, and ordinary glomeruli. The complete identification of glomeruli is important for future studies seeking to explore further the coding mechanisms residing within the primary olfactory center of the moth brain. J. Comp. Neurol. 524:2993-3013, 2016.