Development of odorant receptor neurons in ants

Olfaction-mediated communication is essential for complex social behavior in ants. Odorant receptor (Or) genes were expanded in hymenopteran insects, especially in ants. Mutations in orco lead to the loss of antennal lobe glomeruli in ants, suggesting its essential role in proper olfactory development. We have determined the critical stages when Orco is required for the survival of odorant receptor neurons (ORNs): without orco, ORNs die in the mid- to late-stages of pupal development. This developmental cell death may result from ER stress. Further analyses have revealed the temporal and spatial expression profiles of Or genes, indicating some interesting and perhaps unique features in the ant olfactory development. Our study raises a question of how a different olfactory developmental process was evolved in ants.