Phenology estimates
We gridded our study area into 25 x 25-km equal area cells using the North America Albers Equal Area Conic projection. Community science observations can be biased by organized, public observation events (e.g., iNaturalist’s City Nature Challenge) generating an unusually high number of observations that do not reflect the actual seasonal abundance of a species. We therefore filtered our dataset to include only one observation per day of each species in a year, given each cell. Next, the number of observations for each cell-by-year-by-species combination was counted and deemed usable if at least 10 observations were documented. For each unique cell-year-species combination, we estimated the 0.05 and 0.95 sample quantiles using the quantile() function within the stats R package (R Core Team, 2020) to represent the emergence (first appearance) and termination (last evidence) of adult insect activity. These quantiles are demonstrated to be more robust estimates of phenology than estimating the absolute bounds of a phenophase (Belitz et al. 2020). We calculated the duration of adult insect activity as the difference between the termination and emergence. In total, we used 228,423 records to generate 5,469 emergence, termination, and duration estimates across 626 unique grid cells for 284 species. Over 97% had a basis of record listed as human observation, indicating the vast majority of the data were generated by community scientists.