Characterization of the Anatomy and Organization of the Antennal Lobe in the Asian Corn Borer, Ostrinia furnacalis

The Asian corn borer, Ostrinia furnacalis (Guenée), ranks among the world's most significant agricultural pests and primarily relies on its olfaction to locate food sources, mates, and oviposition sites. The antennal lobe (AL) functions as the primary olfactory center, but detailed knowledge about the AL of O. furnacalis remains scarce. Here, we combined mass staining and synapsin immunostaining, confocal microscopy, and three‐dimensional reconstruction to map the AL glomeruli. We found that the olfactory sensory neurons in antennae and labial‐palp pit organ terminated in distinct AL glomeruli. In total, approximately 69 glomeruli were identified in males and 66 in females. A global comparison revealed sexual dimorphism in glomerular number and size, with three male‐specific glomeruli forming the macroglomerular complex (MGC) and four glomeruli forming the female‐specific glomerular complex (Fx). The MGC accounted for approximately 37% of the total glomerular volume in males, whereas the Fx accounted for 9% in females, suggesting markedly different anatomical investment in sex‐specific olfactory processing. The volume of the labial palp‐pit organ glomerulus was larger in males. Among the ordinary glomeruli, we identified both sexually isomorphic and volumetrically dimorphic glomeruli. This atlas provides a comparative anatomical framework for testing how closely related Ostrinia species encode pheromonal and other ecologically relevant odors.