Directional and fluctuating asymmetry in the black-winged damselfly Calopteryx maculata (Beauvois) (Odonata : Calopterygidae)

Directional asymmetry (DA) has received considerably less attention than fl uctuating asymmetry (FA) in the literature. Evidence for DA, however, is bu ilding among insect taxa. We examined asymmetries in two wing traits within both sexes of the damselfly Calopteryx maculata (Beauvois) (Odonata: Calop terygidae) sampled from three sites in southeastern Ontario. After accounti ng for measurement error, we show that proximal segments within right fore and hind wings are consistently longer than those in the left in all but on e sample group. Full wing lengths, however, exhibited FA rather than DA. Me an asymmetry values for both traits (segment and length) occurred in the di rection of right-wingedness significantly more often than expected by chanc e. Patterns of asymmetry were generally consistent among the sexes and site s, although males tended to exhibit more pronounced DA. We suggest that the wings of C. maculata may undergo compensatory development, so that full le ngths are more bilaterally symmetrical than their component parts.