Potential cryptic diversity between Phyllocnistis insignis populations utilizing Packera dubia as a host plant

The Packera dubia species complex is parasitized by a species of leaf-mining micromoth, Phyllocnistis insignis, that uses plants in the genus Packera as their primary host. Previous research revealed that P. dubia, also known as wooly ragwort, was potentially composed of two species with two varieties each, separated by habitat, morphology, and geography. It was not known whether the moths parasitizing them had similarly speciated or matched the cryptic diversity found in the P. dubia complex. This paper aimed to use DNA barcoding of the cytochrome c oxidase subunit 1 mitochondrial gene to determine the phylogeny of Ph. insignis populations from P. dubia samples collected from four different ecotypes across the Southeastern United States: granite outcrops, the Southern coastal plain, the Atlantic coastal plain, and the Texas-Arkansas-Louisiana tall grass prairies. Ph. insignis barcodes did not reveal clustering relationships that matched the phylogenetic patterns observed in populations of P. dubia, despite their intimately linked geographies, ecologies, and primary-host relationship, but demonstrated minor grouping patterns based on geography. The genetics, phylogeny, morphology, and life history of Ph. insignis have historically been understudied because of difficulties in collection processes and morphological analysis deriving from its small size and elusive habits. Investigations into the phylogeny of Ph. insignis are economically and agriculturally significant because of their close genetic relationship with the invasive leaf-mining moth P. citrella, which parasitizes citrus crops across North America.