Comparing records of exotic insects between citizen science observations and taxonomic collections

Both citizen science observations and taxonomic collections provide valuable data on species occurrences, typically including species identification, as well as the time and place of observation or collection. Comparing these datasets is intuitive and important for understanding biodiversity patterns. In this study, over 86,000 records of exotic insect species in New Zealand were obtained from the Global Biodiversity Information Facility, comprising two record types: citizen science observations (from iNaturalist) and specimen records (from digitised museum collections). These datasets were compared across taxonomic levels, temporal and geographic scales, and species body size. Key differences emerged between the two data sources. Although the total number of exotic insect records was similar, exotic species accounted for a greater proportion of citizen science observations (1 in 5) than specimen records (1 in 10). Taxonomic composition varied significantly between the datasets at the order, family, and species levels, with citizen science observations disproportionately representing larger-bodied species. Consequently, many exotic insect species present in New Zealand were underrepresented in observation records. Despite these biases, the large volume of citizen science data makes it a valuable resource for biosecurity and invasion biology. Enhancing public awareness of diverse insect groups, including smaller or less conspicuous species, could improve data coverage. Ultimately, leveraging the complementary strengths of both record types will enhance biodiversity monitoring and biosecurity efforts.