Graduation Date

Spring 2024

Document Type



Master of Science degree with a major in Biology

Committee Chair Name

Sharyn B. Marks

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Ryan Kerney

Second Committee Member Affiliation

Community Member or Outside Professional

Third Committee Member Name

Karen Kiemnec-Tyburczy

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Catalina Cuellar-Gempeler

Fourth Committee Member Affiliation

HSU Faculty or Staff


Symbiosis, Amphibian, Frog, Algae, Development, Oophila amblystomatis, Rana aurora, Rana sylvatica, Rana cascadae

Subject Categories



The symbiotic relationship between the chlamydomonad green alga Oophila amblystomatis and embryos of certain amphibian species is often presumed to be mutualistic. However, the existence of a mutualism has only been experimentally tested and established in two closely related ambystomatid salamanders. These experiments showed a positive correlation between intracapsular algal density and embryonic growth, survival, hatching synchrony, and hatchling body size. Oophila has been documented within egg capsules of a growing number of amphibian species, including several frogs in the family Ranidae. However, the nature and extent of this relationship remains unclear. Ranid eggs are better oxygenated than ambystomatid eggs, and thus the presence of Oophila may have a reduced influence in ranid hosts compared to ambystomatid hosts. To investigate the symbiotic interaction between ranid eggs and algae, I raised Northern red-legged frog (Rana aurora) and wood frog (Rana sylvatica) egg masses under three light treatments (24-hour light, 12:12 light:dark cycle, and 24-hour darkness). I found that survival, but not hatchling body size, stage at hatching, or rate of development was significantly affected by light treatment in both species, supporting my hypothesis. I also sampled intracapsular fluid from Cascades frogs (Rana cascadae) eggs to determine if Oophila is present in this species. I failed to detect Oophila in the intracapsular fluid using Sanger sequencing, but did detect other algae, which may be indicative of a culturing bias against Oophila. Further research is recommended to ascertain whether Oophila is present or absent in R. cascadae eggs.

Citation Style



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