Short-term impacts of interannual weather variation on insects

Climate change has been proven to be a major driver of insect declines within various habitats across the globe. Its long-term impacts have shown declines in both insect biomass and diversity.  On the other hand, interannual weather variation related to spring timing, summer precipitation, and intensity of winter show short-term impacts on insect communities. In a previous study we conducted in the Long Point World Biosphere Reserve (LPWBR), ON insects were shown to be declining over a 30-year period as a result of climate change. To test how interannual weather variation impacts insect communities in the short-term compared to the long-term impacts of climate change, four sites within the LPWBR were sampled from May to August over three years (2021 – 2023) using malaise traps. Additional aerial netting on a biweekly basis of Hymenoptera and Lepidoptera was also utilized. Insect biomass showed varying trends over the three years, with a significant decline in both insect diversity and terrestrial insect biomass in 2022 associated with a decrease in summer precipitation. Insect diversity and biomass increased again in 2023. This indicates that even though climate change shows a perpetual decline in insects over-time, looking at year-to-year changes in insect communities may show varying trends related to the impacts of more localized weather patterns. The increasing impacts of climate change on insects is vast, but to understand the larger picture of what is happening to insect communities we must also look at the more localized impacts on a short-term scale related to weather.