Glomerular organization of the antennal lobe in the fall webworm Hyphantria cunea (Drury, 1770)

The fall webworm (Hyphantria cunea), a typical destructive invasive pest, has caused substantial damage to both the ecological environment and economy in China. H. cunea uses primarily its antennae to locate food and perceive pheromones through stimulation of olfactory receptor neurons. These receptor neurons project their axons into glomeruli within the antennal lobes, the primary olfactory center in the brain. The projection patterns of sensory antennal neurons into the antennal lobe and its precise structure have not been described so far. To decipher the primary organization behind olfactory recognition in H. cunea, this study employed synaptic antibody immunostaining, as well as mass staining of olfactory sensory neurons (OSNs), and computer-based reconstruction to establish a three-dimensional olfactory glomerular map of the moth's antennal lobes. A total of 74 male and 81 female antennal lobe glomeruli were identified, including 3 male-specific glomeruli (Macroglomerular complex, MGC) and 8 female-specific glomeruli (DL1-DL8). While the Cumulus (Cu) volume was largest in MGC, the differences in volume among dorsomedial anterior and dorsomedial posterior were minimal. These findings lay the groundwork for a better understanding of the olfactory anatomical organization in H. cunea.