New research has revealed that wildfire smoke from Quebec’s 2023 fire season had a surprising effect on forest moths, causing deformed wings in two common species. Published in the journal Environmental Science and Pollution Research, the study found that exposure to wildfire smoke during the larval stage significantly increased the rate of wing deformities in spruce budworm and forest tent caterpillar moths. Researchers collected samples from the Abitibi region of Quebec, where wildfires forced them to halt their studies, creating a natural comparison between samples collected before and after smoke exposure. Spruce budworm moths exposed to smoke were twice as likely to develop folded, crumpled, or missing wings compared to previous years. About 30% of larvae collected after the fires showed wing malformations, compared to 11% to 15% in the prior year. Forest tent caterpillars also showed a similar pattern, but male moths were more severely affected, with more malformations and reduced flight ability compared to lab and field samples collected later. Pheromone traps, which only captured flying moths, caught fewer deformed individuals, suggesting that the deformities may have hindered their ability to fly. The exact mechanism linking wildfire smoke to wing malformations is still unknown. Scientists suspect it could involve hormonal changes during the moth’s transformation from larva to adult or changes in breathing caused by poor air quality. Interestingly, moths with deformed wings were consistently heavier than normal ones, a finding that researchers have yet to explain. They believe it might be due to higher mortality among smaller, weaker individuals, leaving only the larger ones to reach adulthood. Although there was a sharp increase in wing deformations in 2023, the overall moth population in the region remained stable the following year. The researchers emphasize that more studies are needed to understand the long-term impact of wildfire smoke on forest ecosystems, especially as wildfires become more common and severe in Canada’s boreal forest. The findings also raise questions about how wildfires affect biodiversity beyond the fire zone and the complex interactions between insect outbreaks and fire in these ecosystems.