Meeting Abstract

2.3  Jan. 4  Sex and laboratory effects in second-to-fourth digit length ratios (2D4D) in green anole lizards CHANG, J.L.*; DOUGHTY, S.; WADE, J.; LOVERN, M.B.; University of Miami; Oklahoma State Univ.; Michigan State Univ.; Oklahoma State Univ. stynoski@bio.miami.edu

Digit length ratios can show sexual dimorphism related to embryonic steroid exposure. The second-to-fourth digit-length ratio has received the most attention, and previous studies suggest there is species-dependent variation in whether males or females exhibit the larger ratio. In the present study, we measured the 2D4D of all four feet for adult male and female green anoles (Anolis carolinensis) to determine whether this ratio is sexually dimorphic. One investigator at Michigan State University (MSU) and one at Oklahoma State University (OSU) measured the 2D4D of each foot using digital calipers. In addition, to assess to what extent such measurements are repeatable across laboratories, we compared the measurements from MSU to those from OSU. At both laboratories, we found that males had a significantly larger 2D4D ratio on the back right foot than did females, and that no sex difference existed on either the back left or front right foot. However, although no sex difference in the front left foot was found at MSU, the 2D4D on this foot was larger in females at OSU. Our results demonstrate both sexual dimorphism in 2D4D and repeatability between laboratories, but they also suggest the importance of verifying such repeatability if 2D4D or any other digit-length ratio is used as a potential indicator of the early steroid environment. Supported in part by funds from NSF (IBN-0234740) to JW.