Insect species selection and data acquisition
We focused on the five most speciose orders with highly distinct adult forms: Coleoptera (beetles), Diptera (flies), Hymenoptera (bees, wasps, ants, and sawflies), Lepidoptera (butterflies and moths), and Trichoptera (caddisflies). We also include the order Odonata (dragonflies and damselflies) and Cicadidae (cicadas), for which nymphs or larvae are visually distinct from adults and occupy infrequently-surveyed habitats (aquatic and subterranean, respectively). A detailed explanation on the species selection protocol can be found in the Supporting Information.
Within these seven higher-level taxonomic groups, we used overall record counts in iNaturalist to select an initial set of candidate species. We limited searching to research-grade observations (verifiable observations with at least two independent species identifications) and included all insect species in focal groups that had at least 1,000 observations within Canada, the United States, and Mexico as of April 8, 2020. Four-hundred and seventy insect species met our search criteria, representing all our focal higher taxonomic groups except for Trichoptera.
We then further filtered to species primarily observed as adults and maintained those for which at least 99.5% of annotated observations had the life stage annotated as “Adult” by iNaturalist users. Because Lepidoptera are commonly observed as juveniles, we only kept records annotated as adults in our final dataset. Using our final species list, we collected data from GBIF and iDigBio, which aggregate iNaturalist records along with other biological collections. In total, we collected records for 435 species across six insect orders. We limited the temporal scope of our study to the recent years of 2015-2019.