Date of Completion

Spring 5-1-2021

Thesis Advisor(s)

Daniel Bolnick

Honors Major

Biological Sciences


Other Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology


Ecological stoichiometry is a rapidly growing field of study that assesses the elemental composition of organisms in ecosystems and the impact that changes in these elemental compositions have on populations. Parasitism is widely studied for its role in altering the physiology and behavior of hosts within a population. However, the interaction between parasitism and the stoichiometry of the host-parasite system has not been well-established. To determine the impact of parasitism on stoichiometry of host, we measured the elemental composition (%C, %N, and %P) and ratios (C:N, C:P, and N:P) of a population of parasitized and unparasitized Gasterosteus aculeatus (three-spined stickleback) and their parasite, Schistocephalus solidus. Infection presence resulted in an overall decrease in some stoichiometric ratios, specifically C:N, with larger infection intensities resulting in a greater decrease of C:N ratios. Body mass was also an important predictor of infection status and stoichiometry of cestode, as larger hosts had a greater chance of infection and contained larger cestodes with lower carbon, nitrogen, and phosphorus concentrations. These results demonstrate a relationship between stoichiometry and parasitism, but whether variation in elemental composition of host is a cause or a result of parasitism has not yet been determined and requires experimental infections.