Address: 3029 Cordley Hall, Department of Zoology, Oregon State University, Corvallis, Oregon 97331.
Phone: 541.737.5695
Fax: 541.737.0501
Email: parkermi@science.oregonstate.edu
Address: 3029 Cordley Hall, Department of Zoology, Oregon State University, Corvallis, Oregon 97331.
Phone: 541.737.5695
Fax: 541.737.0501
Current research
Intraspecific communication via pheromones is a major reproductive theme across most taxa, and many factors, both abiotic and biotic, control the production and expression of chemical signals. My doctoral research focuses on the proximate mechanisms controlling pheromone production in a classic ectothermic model: the red-sided garter snake (Thamnophis sirtalis parietalis). This species enters a long winter dormancy period (8 months) in the northern extent of its range (Manitoba, Canada). It then emerges in the spring to engage in vigorous, unequivocal reproductive activity. Both sexes produce pheromones (see figure), and the female’s sexual attractiveness pheromone is an extremely powerful sexual signal that relays multiple kinds of information (size, body condition, reproductive state). Some males that emerge in the spring produce a female-typical pheromone and can elicit courtship from other males: there are even instances where these female mimics will court themselves. The physiological control of female mimicry is thought to be related to the biochemical conversion of testosterone to estrogen, and a portion of my research is addressing this issues. Overall, I am attempting to determine the biotic factors signaling/controlling pheromone biosynthesis, with emphasis on sex hormones. I use a variety of analyses to conduct my research: behavioral assays, column chromatography and mass spectrometry, radioimmunoassay, and microsurgical techniques. A recent direction of my research involves the investigation of skin anatomy in an effort to locate sites of pheromone synthesis. To pursue this part of my dissertation, I am using histological techniques, such as ultramicrotome sectioning, for examination with transmission electron microscopy.
Previous research
My Master’s and undergraduate theses both focused on the chemical ecology of rattlesnakes. In Arkansas, I tracked radio-tagged timber rattlesnakes (Crotalus horridus) with Dr. Steve Beaupre and conducted feeding experiments in both the field and laboratory. I observed unique airborne trailing behavior in the snakes during those studies, and I went to Dr. Ken Kardong’s lab at Washington State University to further pursue questions about the chemical ecology of snakes. At WSU, I conducted detailed laboratory experiments of airborne trailing and other foraging behavior patterns in Pacific rattlesnakes (Crotalus oreganus) using a Plexiglas Y-maze (see figure). I also examined the microanatomy and functional morphology of the tongue, sublingual plicae, and vomeronasal ducts of rattlesnakes using both light and electron microscopy (see figures).
General interests
I am interested in reproductive biology, and I hope to explore other aspects of this field in the future (e.g. membrane physiology, pheromone biosynthesis). I consider myself a proximate-level biologist, and I hope to always do research involving the integration of anatomy, physiology, and behavior of organisms. Though I have only worked with reptiles, I hope to pursue research questions in a diversity of animal models in the future. I also have a deep passion for teaching and mentoring students. I have classroom experience in numerous areas of biology, from non-majors introductory biology to comparative vertebrate anatomy. I have mentored a diversity of students in a diversity of research areas. I believe that research experience is the most powerful way to teach people about science and the scientific process. My ultimate goal is to become a professor and have a successful research lab where I can mentor a variety of students (high school to graduate).
