Publication Date
8-2023
Advisor(s) - Committee Chair
Scott Grubbs, Jarrett Johnson, Keith Philips
Degree Program
Department of Biology
Degree Type
Master of Science
Abstract
Leuctra Stephens, 1836 is a genus of Plecoptera (Leuctridae) distributed widely across the Northern Hemisphere, with approximately 210 species reported from eastern North America, Europe, northern Africa, and sporadically across Asia. Eastern North America harbors a small proportion of the global Leuctra fauna (ca. 15% = 31 species), most of which occur in the ancient Appalachian Mountains and unglaciated landscapes in the southeastern USA. Nearctic Leuctra species, except for L. moha and L. crossi, have been divided into five species groups based on external male morphological characteristics. Current phylogenies of Nearctic Leuctra are partial and preliminary, and no comprehensive analyses are available for these species. This study aimed to use molecular methods to assess the validity of the L. ferruginea species group, its two subgroups, and the nine members of the species group as well as determine if L. moha can be placed into the species group. The mitochondrial cytochrome c oxidase subunit 1 (mtCOI) and nuclear 28S ribosomal RNA (28S) genes were sequenced for 403 and 99 individuals, respectively. Sequences were used to generate Neighbor-Joining (NJ), Bayesian Inference (BI), and Maximum Likelihood (ML) trees. Additionally, pairwise comparisons of minimum interspecific and maximum intraspecific differences of mtCOI sequences were implemented to determine genetic distinctiveness. The Automatic Barcode Gap Discovery method further analyzed the pairwise genetic distance matrix to partition individuals into operational taxonomic units (OTUs). The BI and ML trees consistently supported monophyly of the species group with maximum nodal support. There was little evidence to support the distinction of two subgroups as species from different subgroups intermixed and grouped into clades together. Validity of some member species was well-supported with high nodal support and low divergence values (e.g., L. colemanorum, L. hicksi, and L. moha). Others may represent synonymies (e.g., L. szczytkoi and L. paleo, L. alabama and L. rickeri) or cryptic species (e.g., two L. truncata clades, two L. ferruginea clades, and three clades combining L. alabama and L. rickeri). Discovery of synonymous and cryptic species and their integration into biodiversity assessments may affect the protections that are granted to currently described species.
Disciplines
Ecology and Evolutionary Biology | Entomology | Genetics and Genomics | Life Sciences | Molecular Genetics | Terrestrial and Aquatic Ecology
Recommended Citation
Layer, Madison, "A Phylogenetic Analysis of the Leuctra Ferruginea (Walker 1852) Species Group (Plecoptera: Leuctridae)" (2023). Masters Theses & Specialist Projects. Paper 3663.
https://digitalcommons.wku.edu/theses/3663