Date of Award

2015

Degree Name

Environmental Science

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Scott Simonton

Second Advisor

Mindy Yeager-Armstead

Third Advisor

Tom Jones

Abstract

Salinity is increasing in freshwaters throughout the world due to anthropogenic impacts with the implication of the increases to biological communities only now being realized. Declining mayfly populations in Appalachian streams have generated increased interest in elevated dissolved solids in that region and their effect on benthic macroinvertebrates, particularly the sensitive Ephemeroptera taxa. Field and laboratory evaluations have indicated high sensitivity of mayflies to elevated dissolved solids. The research described herein is part of an ongoing effort to provide opportunity for toxicity testing with native mayflies in the laboratory. A successful endeavor would establish mayfly sensitivity to total dissolved solids and evaluate the relationship between the sensitivity of the native taxa and laboratory surrogates. The objective of this study was to investigate methods for rearing field collected, larval mayflies using three types of recirculating culturing systems. Five Ephemeroptera families were collected from streams in central West Virginia. Success of the rearing method was measured by emergence and mortality rates for each individual mayfly taxa. Mayflies are known to reproduce both sexually and asexually, and establishing a parthenogenetic population would allow for a more sustainable laboratory culture and facilitate the use of the taxa in toxicity testing. The ability of field collected mayflies to exhibit parthenogenesis was also examined with emergent adults from the rearing study. Flow in the culturing units was found to be a determining factor of emergence success. The most successful culturing unit based on mayfly emergence was the aquatic plant culturing system (Hexagon) which also generated the highest flow. Of the families evaluated, Baetidae was the only family to have exhibited parthenogenesis. Eggs from the genus Baetis had a hatch rate of 46 percent with incubation ranging from 11-29 days after egg collection. Eggs from the genus Pseudocloeon hatched between 17-24 days and had an average hatch rate of less than 1 percent. Ongoing research has focused on continued improvements in rearing and emergence techniques for native taxa, better understanding of optimal incubation conditions for egg hatch, and increasing survival and longevity of newly hatched larval mayflies.

Subject(s)

Water-supply -- Management -- Environmental aspects.

Mayflies -- Ecology -- Appalachian Region.

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