 Among the insects, Lepidopterans (butterflies and moths) have heterogametic females, but in "Drosophila", males are the heterogametic sex.Heterogamesis can lead to reduced or absent meiotic recombination between the sex chromosomes, and in some species this extends to the autosomes, a phenomenon called achiasmy.For example, most lineages of male "Drosophila melanogaster" flies are achiasmic, lacking recombination on all chromosomes, although females show recombination.