The role of smell in social interactions is significant for both humans and ants, with recent research revealing the importance of a key protein named Orco in the survival of olfactory cells in ants. A study conducted by researchers from New York University and the University of Florida focused on Harpegnathos saltator jumping ants, demonstrating that mutating the orco gene led to a significant decrease in the number of olfactory neurons, highlighting the critical role of Orco in cell development and maintenance. Published in Science Advances, these findings shed light on the cellular and molecular mechanisms underlying social behavior in animals, emphasizing the importance of understanding nervous system development in neuroscience.
Ants, like humans, rely heavily on their sense of smell for communication, with approximately 400 smell receptors allowing them to engage in pheromone communication and cooperative social behavior. This expanded odorant receptor gene repertoire in ants enables them to communicate effectively in large societies comprising hundreds to millions of individuals. Loss of function in odorant receptor neurons can lead to deficits in olfactory sensing, which is associated with social isolation and various neurological disorders in humans. Therefore, studying how ants’ sense of smell influences their social interactions can provide valuable insights into human sensory and communication processes.
To investigate the impact of Orco on olfactory cell development and survival in ants, researchers used genetically engineered ants lacking the Orco protein, which led to changes in their smell organs and difficulty in interacting. Through single-nucleus gene expression profiling and fluorescence microscopy, they found that mutant ants lost most of their olfactory neurons before adulthood, indicating a critical role for Orco in neuronal development and maintenance. This neuronal death could be attributed to stress caused by the inability of odorant receptors to form complexes with Orco, leading to cell death due to organelle clogging and subsequent stress.
Interestingly, even in the absence of Orco, some odorant receptors managed to survive in non-smell cells, such as mechanosensory neurons and glia, suggesting potential new functions for these receptors in different cell types. The abnormal activation of odorant receptor genes in non-smell cells could play a role in evolution by providing existing genes with new functions, expanding the range of sensory capacities in organisms. By unraveling the unique processes of olfactory neural development in social insects like ants, this research enhances our understanding of sensory systems and neural development in the context of social communication.
Overall, this study contributes to the growing body of knowledge on the cellular and molecular mechanisms underlying social behavior and sensory communication in animals, particularly in social insects like ants. By elucidating the role of Orco in olfactory cell development and maintenance, researchers have gained valuable insights into the complex interplay between genetic factors and environmental cues that shape social interactions in organisms. Further research in this area may uncover additional functions of odorant receptors and provide new avenues for exploring the evolution of sensory systems and neural development in different species.