The influence of prenatal versus postnatal conditions
on the physiology of 5 day old kittiwake chicks

The Black Legged Kittiwake (Rissa tridactyla) is a species of Arctic seabird that breeds on coastal cliffs and usually raises two chick broods. Similar to other bird species, kittiwake egg size is correlated with hatchling mass. In older chicks, mass can also be correlated with physiology, including metabolite and hormone levels. However, it is not yet known whether this relationship is due to early postnatal experiences that shape both mass and metabolic and hormonal functions, or whether these aspects of physiology may be predetermined by maternal investment in the egg. If the prenatal experience is the cause of the mass-physiology relationship, then egg mass will be a better predictor of ketone and corticosterone levels than chick mass at 5 days old. We also manipulated the postnatal environment by providing food supplementation to some nests, allowing us to further test the role of post-natal experience in shaping physiology. Experiments conducted on Middleton Island, AK in 2024 studied kittiwake chicks from nests that were provided with food supplementation 3x/day, and control nests that were not supplemented. We measured egg size and mass, as well as chick mass, and corticosterone and ketone levels on day 5 post-hatch. By comparing the ability of egg size versus chick mass to explain ketone and corticosterone levels and survival in both control and experimentally fed nests, our study will provide insight into whether variation in physiology and survival in young chicks is more strongly influenced by prenatal investment or postnatal experiences.

Influences of prenatal and developmental conditions on telomere dynamics in seabird chicks (Rissa tridactyla)

This study investigates the effects of prenatal and postnatal environmental conditions on telomere dynamics in Black-legged Kittiwake chicks (Rissa tridactyla). Telomeres are considered molecular markers for biological aging. They are highly conserved, noncoding, repetitive DNA sequences that form the “caps” at the end of chromosomes, protecting the coding sequences. In some species, variation in telomere length among same-age individuals is associated with individual “quality” and variations in life expectancy. Although higher telomere attrition rates can occur in early development, the inherited and environmental factors driving this physiological process vary by species. In kittiwakes, chicks develop in the nest for over forty days. During this time, chicks are subjected to environmental conditions that affect their growth and longevity. The ensuing study will test the hypothesis that favorable conditions are associated with longer telomeres. We will use blood samples from known-age kittiwake chicks to assess the potential impacts of food availability, sex, hatching order, and sibling competition on chick telomere dynamics. From our hypothesis, we predict that high food availability, status as a first-hatched chick (A chick), and lower sibling competition contribute to maintaining inherited telomere length. Additionally, we will test the hypothesis that rapid growth is associated with longer telomeres at hatching but more rapid telomere loss during development. If this is true, male chicks who grow faster and may have higher metabolic rates will hatch with longer telomeres but show more telomere loss than female chicks.

Investigation of population resistance to cold-induced oxidative damage in a lizard, Sceloporus consobrinus

In ectotherms, metabolic rate positively scales with environmental temperature. We previously demonstrated that prairie lizards (Sceloporus consobrinus) exposed to cold temperatures (18°C) showed an expected decrease in metabolic rate in a lab setting. However, these lizards exhibited a statistically significant increase in levels of oxidative damage to DNA, a harmful metabolic byproduct measured as 8-hydroxy-2’-deoxyguanosine (8-OHdG), due to this cold treatment. Interestingly, cold-induced DNA damage differed by population; lizards from the northern-most population, that experience colder annual temperatures, exhibited no increase in 8-OHdG levels. Oxidative damage following cold exposure in southern populations may be due to the cold exposure itself, or to rapid warming up after the exposure. The purpose of this study is to investigate what specifically underlies the cold-induced increase in the 8-OHdG levels. Adult lizards from the northern and southern populations were exposed to a day-long cold temperature challenge (18°C) in the lab. We measured body temperatures for each lizard immediately following the temperature challenge. To determine the effects of rewarming on 8-OHdG levels, we took blood samples from lizards at the 18°C temperature, to act as a control, and lizards that were placed briefly in a warm incubator after the temperature challenge, which served as our experimental treatment group. Finally, we also measured 8-OHdG levels two days after the temperature challenge to examine the DNA damage repair capabilities of each population. As the climate becomes increasingly unpredictable, understanding how ectotherms physiologically respond to temperature changes is essential for predicting their survival and adaptation.

A Historical and Biological Overview of Leprosy and Typhoid in an Ancient Theban Cemetery

As a PUR Fellow, I was given the opportunity to work closely with Dr. Stephanie Larson to create a written synthesis of the biological and historical backgrounds of leprosy and typhoid in the ancient eastern Mediterranean. My research was separated into two phases: data collection and a written interpretation. I commenced with an in-depth review of literature sources published in both major biological and archaeological publications such as the WHO, CDC, American Journal of Anthropology, and International Journal of Osteoarchaeology. I also annotated and summarized sources provided by Professor Larson to use within my work as well as in her own. Utilizing data from both biological and historical areas of scholarship, I produced reports detailing a pathological overview of leprosy and typhoid, incorporating information dating from ancient records to the modern day. I also generated an essay focusing solely on archaeological cases of leprosy reported across the globe as well as a report of genome mutations occurring in the leprosy causative agent, Mycobacterium leprae. After completion of my written analyses, I compiled all relevant sources into separate bibliographies, one for each disease, for Professor Larson’s use in her own research. My final work will be incorporated into the first volume of the final publication of the Bucknell Thebes Excavation Project, a manuscript currently in progress. My research explored the fascinating connections between science and history and effectively removed the boundary often created between the two fields, providing academics with a well-rounded understanding of the biology and history of both diseases.