Date of Award
Neuropeptide Y, Red-sided garter snake -- Behavior, Immunohistochemistry, Biological rhythms
It is essential for organisms to exhibit appropriate behaviors as they transition from one life-history stage to another. While such life-history transitions are critical to both individual survival and reproductive fitness, we know very little about the underlying mechanisms. This project explores a potential mechanism regulating the transition of red-sided garter snakes (Thamnophis sirtalis) from reproductive to foraging behavior. After emerging from winter dormancy, male snakes engage in mate searching and mating behavior followed by a transition to foraging. Neuropeptide Y (NPY) is a neurohormone that controls appetite and feeding behavior in all organisms studied. We previously demonstrated that NPY cell number in the brain is increased in snakes exhibiting feeding behavior. In this study, we asked if brain NPY is involved in regulating the transition from courtship to foraging behavior under natural field conditions. To address this question, courting and foraging snakes were collected from the field and their behavioral preference confirmed by testing on a Y-maze. Snakes were then euthanized and the brains collected. An immunohistochemistry assay was performed for NPY; immunoreactive cells were counted manually. Quantification of NPY cell number in three different brain regions is currently being finalized (cortex, amygdala, and hypothalamus). We hypothesize that male snakes exhibiting feeding behavior will have more NPY cells than male snakes exhibiting mating behavior. If our hypothesis is supported, these data will provide evidence that NPY plays a role in mediating an important life-history transition between reproductive and feeding behaviors under natural field conditions.
Richards, Daelyn, "Neuropeptide Y: A potential Marker for a Life-History Transition in the Red-Sided Garter Snake (Thamnophis sirtalis)" (2014). University Honors Theses. Paper 105.