An ancient ecosystem speaks volumes: Analyzing speciation events in scrub islands of the southeastern U.S. via their endemics: Melanoplus grasshoppers belonging to the Puer Group

One of the most ancient ecosystems in the southeastern U.S. is scrub, often associated with ridge systems, mainly in Florida, which are thought to have been used as refugia during the sea level rises of the Pleistocene era. Following recession of the waters these habitats effectively remained islands due partly to unique soil composition as well as a relative lack of plant diversity. Thus, scrub is now home to a myriad of floral and faunal endemics. Specifically, this ecosystem is a wellspring of endemism in arthropods, like those in the grasshopper genus, Melanoplus (Orthoptera: Acrididae: Melanoplinae). The majority of the southeastern members of this genus possess short wings, so they are unable to fly. Due to this fact and their propensity to be endemic to specific habitats and southeastern regions, these Melanoplus species are ideal candidates for examining speciation hypotheses. To test such hypotheses, the Puer Group, comprised of 24 species with related morphology, was chosen as it spans four neighboring states (Florida, Georgia, South Carolina, and North Carolina), contains many scrub endemics, and its males are possessed of great variation in their genitalia. Using a number of anonymous SCNPS and known mitochondrial genes, a phylogeny was reconstructed to illuminate the relationships between Puer Group members, the gateway to testing possible modes of speciation, such as cryptic female choice, allopatry, and habitat requirements. Additionally, a novel approach to investigating functional morphology of genitalia will be addressed through the discussion of the applications of micro-CT scans and SEM imaging.