Interactions of land use and climate change disproportionately impact Lepidoptera of the five major insect orders

1. Land use and climate change are two major environmental pressures that interact to impact insect biodiversity. 2. The wide ecological diversity, including life histories, among insects suggests that some groups will be more sensitive to these pressures than others, and it is unlikely that the response of insects in general, as is often assessed in large-scale studies, is representative across insect orders. 3. Using site-level comparisons of insect biodiversity across land uses from a global database, we examine the impact of land use alone and its interaction with climate change on insect richness and abundance. We then compare these results with models that consider varying effects among orders to determine whether some orders are more or less impacted than others. 4. Of the orders assessed, Lepidoptera showed the most extreme differences compared to the average insect response, whereas the Hymenoptera and in some cases the Diptera showed dampened responses. 5. On average, insect species richness and abundance in high-intensity agricultural sites that had also experienced climate change were 33% and 60% lower than in sites of primary vegetation that have not experienced climate change. Compared to this, Lepidoptera had 83% lower species richness and 91% lower total abundance under the same conditions. 6. These results highlight the necessity of exploring the variation within aggregated responses to identify and protect better the most vulnerable groups.