Physiological costs of total cholesterol in European starlings across an urban to rural gradient
Date of Award
Master of Science in Integrative Biology (MSIB)
First Committee Member
Second Committee Member
Urban areas—characterized by high human densities and associated buildings and impermeable surfaces—are increasing globally and represents a leading threat to wildlife that is drastically altering the natural resources they are accustomed to. Prior studies suggest that living in urban habitats can cause wildlife to show increased cholesterol levels; in biomedical research, elevated cholesterol is linked to disease, but the consequence of elevated cholesterol in wildlife remains unclear. We measured total cholesterol in European starlings (Sturnus vulgaris)—an urban adapted species—across an urban and a rural site. We ask: (1) do urban starlings have elevated cholesterol, (2) does elevated cholesterol come at a physiological cost to birds, and (3) to what extent are parental and nestling cholesterol correlated? We found that starlings from urban habitats showed elevated cholesterol compared to rural birds, and this difference increased with age. Cholesterol did not play a role in shaping oxidative damage to DNA, body condition or baseline glucocorticoids, suggesting elevated cholesterol did not come at a physiological cost to starlings. Finally, parental cholesterol was not correlated to their nestlings’ cholesterol. Our results suggest that cholesterol is shaped by urbanization, but this effect is accentuated over the life of a bird perhaps due to differences in diets that accumulate over time. Future work is needed to explore what mechanism drives variation in cholesterol across urban and rural birds, as well as what the long-term consequences of elevated cholesterol may be, if any.
Available for download on Saturday, May 20, 2023