Meeting Abstract

P2.94  Friday, Jan. 4  The burden of gravidity in lizards: changes in cardio-respiratory function associated with reduced lung volume (preliminary results) GILMAN, C.A.*; WOLF, B.O.; University of New Mexico, Albuquerque; University of New Mexico, Albuquerque cgilman@unm.edu

Our previous morphological work on lizards suggests that the volume of growing eggs may result in a significant decrease in lung volume during gravidity. This decrease comes during a period of increased energetic demands because females must both acquire resources to provision eggs, and also bear the burden of transporting the extra mass before laying occurs. Because of the tradeoffs associated with current and future reproduction, particularly the need of individuals to meet their energetic needs during gravidity, we expect to see relative cardiopulmonary compensation during gravity associated with the ecologies of each species. In this study, we investigate how reductions in lung volume affect cardiopulmonary physiology in lizards. To investigate this phenomenon we measured standard metabolic rate, tidal volume, respiratory frequency, and hematocrit and hemoglobin levels in three lizard species; Crotaphytus collaris, Gambelia wislizenii, and Cophosaurus texanus) throughout the reproductive cycle (vitellogenesis to post-laying). Our future research will also include the species Phrynosoma cornutum and Aspidoscelis tesselata. This sample of lizard species varies from actively-foraging, streamlined, relatively low relative-clutch-mass (RCM) species to sit-and-wait, slow moving, and high RCM species. With these data we hope to better understand the evolution of physiology associated with varying foraging ecology, morphology, and life history.