Abstract # 6233 Event # 58:

Scheduled for Thursday, June 18, 2015 04:40 PM-04:55 PM: (Cascade H) Oral Presentation


MORPHOLOGICAL SIGNALS AND MATING SYSTEMS: COMPARING MEASURES OF CRANIAL FLUCTUATING ASYMMETRY AND SECOND-TO-FOURTH DIGIT RATIO IN PRIMATES.

K. S. Clarke1, K. P. McNulty2, A. R. Eller1, J. L. Arenson1, M. Anderson1, E. Simons1, F. J. White1 and S. R. Frost1
1University of Oregon, Department of Anthropology, Eugene, Oregon 97405, USA, 2Department of Anthropology, University of Minnesota, Minneapolis, MN 55455
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     Fluctuating Asymmetry (FA) has been hypothesized to be related to testosterone levels and mating strategies; typically males are more asymmetrical than females. Second-to-fourth digit ratio (2D:4D) is correlated with developmental testosterone levels. Using 2D:4D and cranial FA from 19 primates, we compare the relationship between these variables to their respective mating systems. Forty-five landmarks were digitized using a Microscribe-3DX© for 345 male and 307 female crania. Cranial FA was measured by calculating the Procrustes’ distance between each individual and its mirror-image. Mating systems, classified by intensity and frequency of male aggression, and sex-specific 2D:4D were taken from published studies. Cranial FA and 2D:4D were compared using parametric correlation. Two-way ANOVA of sex and species with a priori multiple comparisons between mating systems was used to examine variation in individual FA. Cranial FA and 2D:4D were correlated (r=-0.460,P<0.05). Cranial FA significantly differed among species (F=64.84,N=19,P<0.05), but there was no difference between sexes (F=1.08,ns) and no sex-species interaction (F=1.24,ns). Multiple comparisons grouping species by mating systems within this ANOVA showed significant differences between pair-bonded and non-pair bonded (F=30.79,P<0.05), between low intensity and high intensity (F=136.76,P<0.05) within non-pair bonded, and between low frequency and high frequency (F=154.62,P<0.05) within high intensity and non-pair bonded. These results support the hypothesis that cranial FA is correlated with testosterone and the variance in male aggression among mating systems.