Effects of Infection of the Protist Parasite, Dermomycoides sp., in Dusky Gopher Frog Tadpoles

<p>Infections of the protist parasite, <em>Dermomycoides</em> sp. are thought to have caused several years of low recruitment in the dusky gopher frog (<em>Rana sevosa</em>) populations. I evaluated the effects of density of the infective zoospores, host developmental stage, and tadpoles' ability to acquire resistance to <em>Dermomycoides </em>sp. on dusky gopher frog tadpoles. Tadpoles were exposed to zoospore densities of 0, 250, 500, and 750 zoospores/µL at Gosner stage 25, and we found no significant differences among treatments in tadpole mortality. In evaluating susceptibility by development stage, I exposed <em>R. sevosa</em> to 50 zoospores/µL as eggs, embryos, hatchlings, and 2-weeks post hatching tadpoles. Hatchlings (17 days, SE = 2.09 days) and tadpoles exposed 2-weeks post-hatching (17.65 days, SE = 1.48 days) had a significantly lower days to mortality than tadpoles exposed as eggs(27.56 days, SE = 2.09 days) or embryos ( 25.81 days, SE = 2.09 days). To assess if gopher frog tadpoles can acquire resistance to <em>Dermomycoides</em> sp. I exposed tadpoles around Gosner stage 25 to an initial zero (0 zoospores/µL), low (50 zoospores/µL), or high (250 zoospores/µL) dose of <em>Dermomycoides </em>sp. Two-weeks later each treatment was exposed to a second zero, low, or high dose for a total of 9 treatments. Survival was lowest in tadpoles that received a low initial dose followed by a zero or high challenge dose (0 and 3.03% respectively). I found that gopher frog tadpoles can acquire resistance to <em>Dermomycoides</em> sp., and that age at initial exposure plays an important role in tadpole survival.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2020

Author dc:creator

• Smith, Jaime

Contributors dc:contributor

• Robert Griffitt
• Robin Overstreet
• Zachary Darnell

• endangered species
• disease
• amphibian
• parasite
• Parasitology
• Terrestrial and Aquatic Ecology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/775

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1827