M. Andrew Johnston‡, Evan S. Waite§, Ethan R Wright§, Brian H. Reily§, Gilma Juanita De Leon§, Angela Iran Esquivel§, Jacob Kerwin§, Maria Salazar§, Emiliano Sarmiento§, Tommy Thiatmaja§, Sangmi Lee§Corresponding author: M. Andrew Johnston ( ajohnston@asu.edu ) © M. Andrew Johnston, Evan Waite, Ethan Wright, Brian Reily, Gilma De Leon, Angela Esquivel, Jacob Kerwin, Maria Salazar, Emiliano Sarmiento, Tommy Thiatmaja, Sangmi Lee. This is an open access preprint distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation:
Johnston MA, Waite ES, Wright ER, Reily BH, De Leon GJ, Esquivel AI, Kerwin J, Salazar M, Sarmiento E, Thiatmaja T, Lee S (2023) Insect collecting bias in Arizona with a preliminary checklist of the beetles from the Sand Tank Mountains. ARPHA Preprints. https://doi.org/10.3897/arphapreprints.e101994 |  |
The state of Arizona in the southwestern United States supports a high diversity of insects. Digitized occurrence records, especially from preserved specimens in natural history collections, are an important and growing resource to understand biodiversity and biogeography. Underlying bias in how insects are collected and what that means for interpreting patterns of insect diversity is largely untested. To explore the effects of insect collecting bias in Arizona, the state was regionalized into specific areas. First, the entire state was divided into broad biogeographic areas by ecoregion. Second, the 81 tallest mountain ranges were mapped onto the state. The distribution of digitized records across these areas were then examined.
A case study of surveying the beetles (Insecta, Coleoptera) of the Sand Tank Mountains is presented. The Sand Tanks are low-elevation range in the Lower Colorado River Basin subregion of the Sonoran Desert from which a single beetle record was published before this study.
The number of occurrence records, collecting events, and taxa are very unevenly distributed throughout Arizona and do not strongly correlate with geographic size of areas. Species richness is estimated for regions in Arizona using rarefaction and extrapolation. Digitized records from the disproportionately highly collected areas in Arizona do not begin to represent the total insect diversity within them. We report a total of 141 species of coleoptera from the Sand Tank Mountains based on 914 digitized voucher specimens. These specimens add important new records for taxa that were previously unavailable in digitized data and highlight important biogeographic ranges.
Possible underlying mechanisms causing bias are discussed and recommendations are made for future targeted collecting of undersampled regions. Insect species diversity is apparently at best 70% documented for the state of Arizona with many thousands of species not yet recorded. The Chiricahua Mountains are the most densely sampled region of Arizona and likely contain at least 2,000 species not yet vouchered in online data. Preliminary estimates for species richness of Arizona are at least 21,000 and likely much higher. Limitations to analyses are discussed which highlight the strong need for more insect occurrence data.