Meeting Abstract
Prolonged water restriction in arid environments is a potential source of physiological stress to xeric-adapted animals, like desert iguanas (Dipsosaurus dorsalis). Such animals may maintain allostasis by adjusting behavior, physiology, and/or morphology to reduce unnecessary water loss and minimize adverse physiological effects of the stressor(s). However, animals must perceive events as a stressor and transduce the information into neural and hormonal responses to facilitate necessary changes. Corticosterone (CORT) is a stress hormone that helps to mobilize energy stores and suspend unnecessary activities. We predicted that populations of D. dorsalis that were under water restriction would have higher baseline CORT levels than populations with access to supplemented water through urban irrigation. We measured hematocrit (an indication of dehydration), and baseline CORT levels of two urban populations of D. dorsalis, one with and without (“natural”) access to irrigated landscaping, in Rancho Mirage, CA in August during the driest part of their active season. Although hematocrit levels from the “natural” site were significantly higher than those from the irrigated site, there were no significant differences in baseline CORT between populations, and no evidence of a significant interaction between site and hematocrit on baseline CORT concentrations. Further analysis of D. dorsalis behavior and stress levels upon acute stress are needed to evaluate the entirety of their physiological stress responses to water restriction.
