Abstract # 6232 Event # 52:

Scheduled for Thursday, June 18, 2015 04:10 PM-04:25 PM: (Cascade H) Oral Presentation


BERGMANN'S RULE IN SKULL SIZE AND CLINAL VARIATION IN SKULL SHAPE OF WILD VS. CAPTIVE FASCICULARIS GROUP MACAQUES

J. L. Arenson, M. Anderson, A. Eller, E. Simons, F. J. White and S. R. Frost
University of Oregon, 308 Condon Hall, Eugene, Oregon 97403, USA
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     Bergmann’s rule predicts that body size increases with distance from the equator. This pattern has been noted in wild macaque populations, but relocated captive populations have not yet been examined for the cline. They are therefore a prime population for analyzing whether Bergmann’s rule is influenced more by natural selection or developmental plasticity. Forty-five 3D cranial landmarks were collected using a Microscribe-3DX on a sample of 251 adult crania from wild populations of Macaca fascicularis, M. cyclopis, M. fuscata and M. mulatta with known provenience, as well as 18 captive M. mulatta from Beaverton, OR (lat=45.5) and 40 from Cayo Santiago, Puerto Rico (lat=18.2). Centroid size was calculated for each specimen as a proxy measure of body size. Shape was assessed with a 2-Block Partial Least Squares (2B-PLS) analysis between geographic and shape coordinates. Centroid sizes and 2B-PLS scores were regressed against the distance from the equator. For wild macaques, distance from the equator was significantly correlated with both size (males R2=0.370; p=0.00; females R2=0.475; p=0.00) and shape (males R2=0.529, p=0.00; females R2=0.504, p=0.00). Predicted latitudes based on cranial sizes (Beaverton=38.0; Cayo Santiago=44.9) were much larger than their respective current locations but were much smaller when based on shape (Cayo Santiago=13.3; Beaverton=8.5). These results suggest that phenotypic plasticity may play an important role in the latitudinal pattern of skull size in wild fascicularis group macaques.