Wings and bristles: character specificity of the asymmetry phenotype in insecticide-resistant strains of Lucilia cuprina

We investigated the hypothesis that observed higher levels of asymmetry dis played by insecticide-resistance genotypes of Lucilia cuprina are restricte d to bristle characters, due to the action of resistance genes in bristle c ell development, rather than through the disruption of genomic coadaptation . We compared the level of asymmetry of three bristle characters and three wing characters in non-modified-and modified-resistance genotypes. Consiste nt with previous studies, resistance genotypes displayed greater levels of bristle asymmetry than either susceptible or modified genotypes. However, t here were no differences among genotypes for any of the wing characters. To confirm that this result is attributable to the action of the resistance a nd modifier genes themselves, we also examined the responses of both bristl e and wing characters to the more general developmental stress of extreme t emperature. Sub-optimal temperature was shown to increase both bristle and wing asymmetry, suggesting that there are no underlying differences between the two character types which could, of themselves, explain the differenti al response observed in the resistance genotypes.