Counting animal species with DNA barcodes: Canadian insects

Abstract

Recent estimates suggest that the global insect fauna includes fewer than six million species, but this projection is very uncertain because taxonomic work has been limited on some highly diverse groups. Validation of current estimates minimally requires the investigation of all lineages that are diverse enough to have a substantial impact on the final species count. This study represents a first step in this direction; it employs DNA barcoding to evaluate patterns of species richness in 27 orders of Canadian insects. The analysis of over one million specimens revealed species counts congruent with earlier results for most orders. However, Diptera and Hymenoptera were unexpectedly diverse, representing two-thirds of the 46 937 barcode index numbers (=species) detected. Correspondence checks between known species and barcoded taxa showed that sampling was incomplete, a result confirmed by extrapolations from the barcode results which suggest the occurrence of at least 94 000 species of insects in Canada, a near doubling from the prior estimate of 54 000 species. One dipteran family, the Cecidomyiidae, was extraordinarily diverse with an estimated 16 000 species, a 10-fold increase from its predicted diversity. If Canada possesses about 1% of the global fauna, as it does for known taxa, the results of this study suggest the presence of 10 million insect species with about 1.8 million of these taxa in the Cecidomyiidae. If so, the global species count for this fly family may exceed the combined total for all 142 beetle families. If extended to more geographical regions and to all hyperdiverse groups, DNA barcoding can rapidly resolve the current uncertainty surrounding a species count for the animal kingdom. A newly detailed understanding of species diversity may illuminate processes important in speciation, as suggested by the discovery that the most diverse insect lineages in Canada employ an unusual mode of reproduction, haplodiploidy.This article is part of the themed issue ‘From DNA barcodes to biomes’.

Arthropods of Canadian grasslands: a retrospective of a 40-year project of the Biological Survey of Canada

“…Diverse groups thought to contain many undescribed or unrecorded species included Acari, Hemiptera, Coleoptera (especially Staphylinidae), Lepidoptera (especially Tineoidea), and particularly Diptera and Hymenoptera. The question of arthropod diversity in Canada was revisited by Hebert et al (2016), who used results of DNA barcoding to reassess these earlier estimates. They concluded that there may be more than 100 000 species of insects in Canada, including as many as 50 000 species of Diptera and 30 000 species of Hymenoptera.…”

“…Comparison of the available checklists with predictions of total species richness from DNA barcoding studies (e.g., Hebert et al 2016, Sheffield et al 2017 shows that our knowledge of grassland arthropods is incomplete, except in the best-known taxonomic groups. Many checklists, including some of those summarised above, result from sampling brief windows of opportunity during the collecting season, perhaps as little as a few hours on one day of the year.…”

Indobiosys – Dna Barcoding as a Tool for the Rapid Assessment of Hyperdiverse Insect Taxa in Indonesia: A Status Report

“…Barcode of Life) have produced big amount of data to populate BOLD's global database of DNA barcodes (Hendrich et al 2014, Morinière et al 2014, Hendrich et al 2015, Schmidt et al 2015, Hawlitschek et al 2016, Hebert et al 2016.…”

Contribution of DNA barcoding to the study of the bees (Hymenoptera: Apoidea) of Canada: progress to date

“…Since then, taxonomic advances (including new molecular taxonomy tools) have improved the knowledge base for many groups. For example, Hebert et al (2016) used DNA barcoding to estimate more than 94 000 insect species in Canada, about a 58% increase over Danks (1979) estimate, with Diptera and Hymenoptera (especially Parasitica) being "unexpectedly diverse" and in general poorly known.…”