Jenna Petrie
Pronouns: She/her
Research Mentor(s): Kristel Sanchez
Research Mentor School/College/Department: Ecology and Evolutionary Biology / LSA
Program: UROP
Session: Session 4 (1:40pm – 2:30pm)
Authors: Kristel Sanchez, Jenna Petrie, Meghan Duffy
Abstract
The majority of organisms on Earth have the ability to selectively feed which increases feeding efficiency by consuming more nutritious foods and avoiding toxic diets. In terrestrial systems, there are some organisms with the ability to self-medicate by selectively feeding on toxic diets to help them cope with parasites. Within aquatic ecosystems, there are no reported examples of animals that can self-medicate. Past research has shown that cyanobacterial diets can protect aquatic hosts from parasites. In this project, we will evaluate whether the freshwater zooplankton Daphnia can selectively feed and, can they self-medicate when challenged by a fungal parasite. We fed Daphnia dentifera 3 different diets. The first diet contained only Ankistrodesmus falcatus, a type of green algae that is considered a nutritious diet. The second treatment diet contained a 50:50 ratio of Ankistrodesmus to Microcystis aeruginosa strain CYA43, which is toxic to Daphnia but does not produce the well-known group of toxins, microcystins. The last diet treatment contained a 50:50 ratio of Ankistrodesmus to Microcystis aeruginosa strain CYA160, which produces microcystins. We then exposed those animals to the fungal parasite Metschnikowia bicuspidata. We collected data on infection prevalence, parasite spore reproduction, host offspring production, host mortality, and measured algal abundance in beakers before and after parasite exposure. Preliminary results show that Daphnia fed Microcystis CYA43 had fewer infections compared to animals fed Microcystis CYA160 and Ankistrodesmus that were exposed to Metschnikowia spores. We expect that if Daphnia have the ability to self-medicate, infected organisms would feed more on CYA43 (which reduces infection) than Ankistrodesmus, therefore we expect the abundance of CYA43 post-feeding would increase for animals challenged with the parasite. This research aims to provide the first evidence of self-medication in aquatic ecosystems and also determine whether Daphnia respond differently to different diets and parasites. While this research helps us gain a better understanding of Daphnia and other aquatic organisms, it also has its own implications within the medical world as we look for alternative ways that humans can protect themselves from disease and parasites.
