Borrowing the Pentatomomorpha tome from the DNA barcode library: Scanning the overall performance ofcox1as a tool

Abstract

Pentatomomorpha (Hemiptera: Heteroptera) occurs worldwide with almost 19,000 species within six superfamilies. Their wide morphological, behavioral, and ecological diversity is remarkable, making them subject of basic and applied studies. The mitochondrial cytochrome c oxidase subunit I (cox1) proposed as a DNA barcode for Metazoa is used in species discovery and identification, relying on threshold values to split intra- and interspecific sequences and a comprehensive library to accurate identification. Here, we scanned all the pentatomomorphan cox1 sequences on Barcode of Life Data System library aiming to provide an overview of available data; verify barcoding gaps at generic level; infer individual empirical threshold values to distinguish congeneric species; and test efficiency of cox1 based on the Probability of Correct Identification (PCI) analysis. Our final dataset comprised 12,189 sequences, covering five superfamilies, 32 families, 460 genera, and 1068 species. The dataset abundance and composition were biased to families with economic importance, that is, Pentatomidae, Lygaeidae, Scutelleridae, Coreidae, and Rhyparochromidae. Barcode gaps were detected for most of the analyzed genera, reaffirming the efficiency of cox1 for Pentatomomorpha. We inferred threshold values for 131 genera and found a global PCI of 74.33%, suggesting that one out of four analyzed species suffer from operational biases or hide cryptic species. We brought examples to illustrate how cox1 can be used to flag inconsistencies, refine, and shed light onto future studies on Pentatomomorpha. We emphasize the efficiency of cox1 as DNA barcode for these true bugs, advocating for its combined use with, for example, morphology in integrative approaches.