BILATERAL SYMMETRY AND SEXUAL SELECTION - A METAANALYSIS

A considerable body of primary research has accumulated over the last 10 yr testing the relationship between developmental instability in th e form of fluctuating asymmetry and performance of individuals in mati ng success itself or sexual attractiveness. This research comprises 14 6 samples from 65 studies of 42 species of four major taxa. We present the results of a meta-analysis of these studies, which demonstrates t hat there is indeed an overall significant, moderate negative relation ship: for studies, the overall mean Pearson's r or effect size = -.42, P < .0005; for species, the overall mean r = -.34, .01 < P < .025. Ba sed on calculated fail-safe numbers, the effect-size estimates are hig hly robust against any publication or reporting bias that may exist. T here is considerable evidence that the magnitude of the negative corre lation between fluctuating asymmetry and success related to sexual sel ection is greater for males than for females, when a secondary sexual trait rather than an ordinary trait in studied, with experimentation c ompared with observation, and for traits no involved with mobility com pared with traits affecting mobility. There is also limited evidence t hat higher taxa may differ in effect size and that intensity of sexual selection negatively correlates with effect size.