bioRxiv preprint doi: https://doi.org/10.1101/274431; this version posted March 14, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Quantifying the unquantifiable: 2 why Hymenoptera – not Coleoptera – is the most speciose animal order 3 4 Andrew A. Forbes, Robin K. Bagley, Marc A. Beer, Alaine C. Hippee, & Heather A. Widmayer 5 University of Iowa, Department of Biology, 434 Biology Building, Iowa City, IA 52242 6 7 Corresponding author: 8 Andrew Forbes 9 10 Email address:
[email protected] 11 12 13 1 bioRxiv preprint doi: https://doi.org/10.1101/274431; this version posted March 14, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 14 Abstract: We challenge the oft-repeated claim that the beetles (Coleoptera) are the most species- 15 rich order of animals. Instead, we assert that another order of insects, the Hymenoptera, are more 16 speciose, due in large part to the massively diverse but relatively poorly known parasitoid wasps. 17 The idea that the beetles have more species than other orders is primarily based on their 18 respective collection histories and the relative availability of taxonomic resources, which both 19 disfavor parasitoid wasps. Since it is unreasonable to directly compare numbers of described 20 species in each order, we present a simple logical model that shows how the specialization of 21 many parasitic wasps on their hosts suggests few scenarios in which there would be more beetle 22 species than parasitic wasp species.