Biologists that study animal evolutionary ecology and ecological energetics often want to quantify the timing of reproduction and the energetic investment made by animals living under varying environmental conditions. Many researchers are also interested in quantifying the energy stores that are accumulated as discrete fat bodies contained within the abdomens of small animals such as lizards. Traditionally, these characteristics have been measured destructively by removing a number of individuals from a population and measuring egg size, number, and fat body mass in specimens after they have been euthanized. The current methodologies place limits on our ability to understand animal evolutionary ecology and energetics because a single individual can only be sampled once, which prevents following the reproductive performance of individuals through a reproductive season or across years. This research addresses the critical issue of how can we accurately measure the same animal's reproductive effort over the course of a single reproductive season or the animal's lifetime. This project validates the use of portable ultrasound imaging systems for quantifying the reproductive effort and energetic status of small animals such as lizards. During this project, the methodology will be developed for using ultrasound imaging to obtain highly repeatable field measurements of small structures such as eggs and fat bodies in small animals and see how strongly these measurements can be correlated with the energy content of these structures. This study will engage at least one undergraduate student in the research enterprise from study design and implementation through data collection, synthesis and presentation.
