Effects of elevated ozone on life history traits, olfactory detection, and behavior in Drosophila

Rising ozone levels pose a significant threat to the ecological balance and biodiversity of insects. Previous research has shown that high ozone levels can disrupt volatile organic compounds (VOCs), which affects insect foraging and mating behavior. However, comprehensive studies examining how ozone affects insect fitness, olfactory behavior, and physiology remain limited. To address this gap, we exposed Drosophila melanogaster to ozone concentrations comparable to those found in polluted urban environments for four days. We then assessed the flies' general fitness, along with their neuronal and behavioral responses to odors. While the flies' general fitness was not clearly affected, we observed that ozone exposure modified their olfactory behavior. Flies exposed to ozone showed significantly reduced responses to specific attractive single and complex odors, while their aversion to repulsive odors increased. To investigate the underlying neurophysiological consequences, we employed functional imaging and electrophysiological experiments to monitor odor responses in olfactory sensory neurons, revealing subtle alterations in neuronal processing. Additionally, RNA sequencing revealed that ozone exposure induced subtle yet coordinated transcriptional changes in sensory tissues and brain consistent with a conserved stress-adaptive response. Together, these findings highlight how air pollutants can influence insect olfactory perception and behavior, offering new insights into the broader ecological consequences of atmospheric pollution and opening avenues for future research.