FLUCTUATING ASYMMETRY IN VESTIGIAL AND FUNCTIONAL TRAITS OF A HAPLODIPLOID INSECT

If natural selection on fluctuating asymmetry (FA) is common and relat ed to trait functionality, then vestigial traits should show elevated FA. Moreover, if FA increases with heterozygosity, then haploid males of haplodiploid taxa should exhibit higher FA than diploid females. We measured fluctuating asymmetry of functional traits (fore femora of s oldier morphs and disperser morphs, and wings of dispersers) and a ves tigial trait (wings of soldiers) in the eusocial haplodiploid gall thr ips Oncothrips tepperi (Insecta: Thysanoptera). Wing FA, but not femur FA, was substantially and significantly higher in soldiers than in di spersers in both sexes. Patterns of intersexual variation in FA were c omplex: for wings, female soldiers had higher FA than male soldiers bu t male dispersers had higher FA than female dispersers, and for femora , males and females did not differ in FA in either morph. Our results suggest that vestigial traits exhibit higher FA because of relaxation of selection for functionality, and that haploidy does not necessarily lead to increased FA in males of haplodiploid taxa.