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

Directional asymmetry (DA) has received considerably less attention than fluctuating asymmetry (FA) in the literature. Evid ence for D A, howev er, is building am ong insect tax a. We ex amined as ymmetries in two wing traits within both sex es of the dam selfly Calopte ryx mac ulata (Beauvois) (Odonata: Calopterygidae), sampled from three sites in southeastern Ontario. After accounting for measurement error, we show that proximal segments within right fore and hind wings are consistently longer than left in all but one sample group. Full wing lengths, however, exhibited fluctuating rather than directional asymmetry. Mean asymmetry values for both traits (segment and length) occurred in the direction of right-wingedness significantly more often than expected by chance. Patterns of asymmetry were generally consistent among the sexes and sites, although males tended to exhibit more pronounced DA. W e suggest that the w ings of C. mac ulata may undergo compensatory development such that full lengths are more bilaterally symmetric than their comp onent parts.