Publication Date

Spring 2020

Advisor(s) - Committee Chair

Scott Grubbs (Director), Jarrett Johnson, Albert Meier

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

Stoneflies (Plecoptera) are often associated with cold perennial streams, but many species also inhabit intermittent streams that experience reduced or lack of flow during summer and autumn. In this study the influence of stream permanence on stonefly assemblage composition and spatial distribution in the Mammoth Cave region, Kentucky, USA, was addressed based on a 14 month sampling regime from the fullest range of stream sizes and habitable flow regions available. Adult stoneflies were collected monthly at Mammoth Cave National Park and the Western Kentucky University Green River Preserve. Collections were done from December 2018–October 2019 using a standard timed protocol with beating sheets for adults and once in December 2019– January 2020 for larvae. Stream sites were assigned one of five category types: perennial spring runs, perennial spring seeps, upland perennial streams, perennial riverine, and summer dry runs. In total, 34 species were collected. The most prominent difference in stonefly community structure was between perennial spring runs, seeps, and the summer dry streams vs. upland perennial streams. Approximately 88% of species collected had univoltine-fast life cycles and 79% had a period of diapause. Species that are able to survive in intermittent habitats do so by life history adaptations including mechanisms to survive desiccation as larva or egg. Additionally, gene flow and genetic structure was examined from two stoneflies in the same genus (Leuctra schusteri and Leuctra alta) with differing life history strategies. Leuctra schusteri is expected to have decreased gene flow across the region when compared to L. alta due to being restricted to perennial flow systems. To test this, the mitochondrial cytochrome c oxidase subunit I gene (mtCOI) was sequenced from 29 L. schusteri individuals of from six locations and of 47 L. alta individuals from 9 locations. Sequences were aligned using MUSCLE in MEGA X and compared using pairwise Fst and Gst tests and AMOVAs. The results from pairwise tests and AMOVAs supported the initial hypothesis that L. schusteri had decreased gene flow and genetic diversity between populations when compared to L. alta.

Disciplines

Biodiversity | Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology

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