Date of Award
Spring 5-6-2024
Document Type
Honors Thesis
Department/Major
Biology
First Advisor
Jacob Kerby
Second Advisor
Jeff Wesner
Third Advisor
David Swanson
Keywords
Selenium, Batrachochytrium dendrobatidis, American bullfrogs
Subject Categories
Biology
Abstract
Most amphibians in today’s world are exposed to a variety of environmental stressors. This project’s main objective was to determine any effects of selenium on Batrachochytrium dendrobatidis (Bd) and infection levels in South Dakota amphibians. I selected American bullfrogs (Rana catesbeiana) as they are susceptible to Bd and are found throughout eastern South Dakota. The secondary objective of this project was to measure any impact of Bd and selenium, combined, on growth measures of the frogs. The third objective was to see if survival rates were reduced when amphibians were exposed to Bd and selenium. Tadpoles were collected (n=225) from the Gavins Point Fish Hatchery in Yankton, SD and were separated into nine groups (25/treatment). Ventral-cloacal swabbing was performed and analyzed using qPCR to determine Bd levels. Growth was recorded (mass and SVL) via the use of electronic calipers. Survival data were collected daily throughout the experiment. I found the highest levels of Bd infection where individuals were exposed to both selenium and Bd, yet no impact of time was found (Table 1 and Figure 1). Tadpoles decreased in mass while increased in SVL across all treatment groups. I found no effects of treatment on either measure of growth or on survival, yet do highlight that the survival rates was lower overall (~50%). These data indivate that low levels of selenium might not otherwise impact American Bullfrog tadpoles, but do not appear to lead to increased infection levels when exposed to Bd. This finding suggests that further attention should be paid to this important contaminant in understanding its role in disease dynamics in South Dakota.
Recommended Citation
Morrison, Taylor, "Measuring the Effects of Selenium Exposure on Batrachochytrium dendrobatidis (Bd) Growth in vivo in Larval American Bullfrogs (Rana catesbeiana)." (2024). Honors Thesis. 331.
https://red.library.usd.edu/honors-thesis/331