Meeting Abstract
Across vertebrates, red blood cells transport oxygen throughout the body. Generally, the oxygen capacity of the blood varies with temperature and altitude, such that animals inhabiting environments with cooler temperatures and those that occur at higher elevations must compensate for the resulting decrease in blood flow rate and consequential lack of oxygen transport. These compensatory traits can include larger red blood cells, greater hematocrit (the percentage by volume of red blood cells in the blood), and a higher concentration of hemoglobin (a protein in red blood cells that transports oxygen). In this study, we measured these blood physiology traits in adult males in a group of 13 Anolis lizard species that occur across a wide range of elevations (10 to 1500 meters above sea level) in the Dominican Republic. We also collected altitudinal data from each population studied, and body temperature measures for a subset of 8 of these species. We observed extensive interspecific variation in each of the hematological traits, but this variation was not associated with microhabitat specialization (i.e., ecomorph) or body temperature, and no phylogenetic signal was detected in the traits. Using phylogenetically-informed analyses, we found marginally positive relationships between hemoglobin concentration and altitude, and between hemoglobin concentration and hematocrit. Together, these results suggest that characteristics of blood related to oxygen transport capacity in anole lizards may evolve in association with a complexity of ecological factors.
