Meeting Abstract

12.3  Monday, Jan. 4  The energetic costs of different components of the social display in male Brown Anoles. STEFFEN, J.E.*; APPEL, A.G.; Auburn University steffje@auburn.edu

Male Anoline social displays are dynamic and typically consist of several different components (e.g., head nods, dewlap extension, and two and four legged push-ups), which appear to be physically costly. Studying the energetics of these different display components may allow us to define the limits of sexual selection by designating which display components are significantly energetically expensive, and which may then act as a form of fitness cost. To investigate the energetic expense of these display components, we quantified oxygen consumption (VO2) of displaying male Brown Anoles. We placed focal adult males in transparent respirometry chambers that were 5 cm away from a size-matched male and a female (both in separate, transparent plastic boxes). We performed Flow-through respirometry on the focal male to determine male oxygen consumption while engaged in social displays. We used an event recorder program to count the number and duration of all display components, and we obtained oxygen consumption values for each display component that occurred. Multiple regression of display VO2 against real-time sums of the display component O2 consumption rates revealed that push up and head nod frequency were the only components to explain a significant variation in display VO2. These results imply that components of display behavior such as dewlap extensions and head nods are relatively energetically inexpensive, whereas 2 and 4-legged push-ups are more costly. These findings may have implications for understanding which components of the Anoline display are under significant sexual selection.