Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.S. in Biological Science

First Advisor

Colin R. Jackson

Second Advisor

Gregg Roman

Third Advisor

Susan Balenger

Relational Format



Juvenile dragonflies (nymphs) may possess the ability to pass their microbiome to the adult life stage through metamorphosis. If this is so, the environment in which the nymph develops may have an effect on the adult microbiome. In this study, the gut microbiomes of 13 species of dragonfly were compared across life stages and when collected from environments at different levels of urbanization. The gut of each dragonfly was removed, DNA extracted, and a portion of the bacterial 16S rRNA gene amplified and sequenced. Gut suspensions were also plated on antibiotic amended plates to determine the potential for dragonflies to contain antibiotic resistant bacteria. Gut microbiomes of dragonflies mainly separated by life stage, with nymphs further separating by the environment from which they were collected from. Dragonfly species was not a significant factor in the separation of either nymph or adult microbiomes. The microbiomes of nymphs and adults differed in levels of their dominant bacterial phyla, with Proteobacteria being dominant in adults, while nymphs shoa higher proportion of Acidobacteria and Bacteroidetes compared to adults. Nymphs also contained bacteria phyla that were not present in the adult microbiome. Both life stages contained antibiotic resistant bacteria, with the guts of dragonfly adults having higher counts of resistant bacteria than nymphs. The environment from which the dragonflies were collected had a significant influence on the counts of resistant bacteria for multiple antibiotics, as did dragonfly species. These results suggest that the gut microbiomes of dragonfly nymphs and adults are fundamentally different, and that both life stages have the potential to contain antibiotic resistant bacteria. The local environment influences both the numbers of these antibiotic resistant bacteria and the composition of the gut microbiome in general.

Included in

Biology Commons



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