Graduation Year
2025
Document Type
Campus Only Senior Thesis
Degree Name
Bachelor of Arts
Department
Biology
Reader 1
Sarah Budischak
Reader 2
Elise Ferree
Terms of Use & License Information
Abstract
Emerging infectious diseases have significant global impacts which can result in the decline of wildlife populations, loss of human lives, cause spillovers, and even have strong economic impacts, among other consequences. Three key variables that can influence the mechanisms of disease transmission are infection, body condition, and chronic stress. Infection has been associated with poor host survival and condition, while costs of chronic stress include immunosuppression as well as decreased body condition, growth rate, and reproductive success. It is evident that the relationships among infection, condition, and chronic stress are deeply intertwined, however, they are complex, continuous variables, and directionality has not been well established. To disentangle the relationships among infection, condition, and chronic stress, we conducted an observational, longitudinal study focusing on recaptured Gambel's White-crowned Sparrows (GWCS). We defined stress by heterophil to lymphocyte (H/L) ratios and used the body mass and wing chord as an indicator of body condition. In addition, we measured Leucocytozoon, Haemoproteus, and Plasmodium infections. For this study, we analyzed data collected in the Bernard Field Station in Claremont, CA, that spanned across six years (2018-2024). By repeatedly testing the same individuals over time, we were able to better establish causal relationships, for example by observing if higher chronic stress levels preceded infection presence. We found that infection and chronic stress had significant effects on infection status and chronic stress at the recapture. We also found significant seasonal variation in stress and condition, and that age had significant effects on body condition. This study sought to establish clearer directionality among these relationships, bringing us closer to understanding the mechanisms and patterns of infectious disease in wildlife populations.
Recommended Citation
Jue, Malia, "Disentangling the Relationships Among Infection, Stress, and Body Condition in a Migratory Songbird" (2025). Scripps Senior Theses. 2526.
https://scholarship.claremont.edu/scripps_theses/2526
This thesis is restricted to the Claremont Colleges current faculty, students, and staff.
