Sex-linked inversions in blackflies (Diptera:Simuliidae).

The family Simuliidae exhibits a diversity of sex-linked inversions which fall into four major classes. Inversions occur which are found only in the X or Y, and these may be fixed or polymorphic. Y-linkage is clearly commoner amongst such inversions. Other inversions are found which phylogenetic evidence suggests cannot have been sex-linked in ancestral species, but have become so in derived forms. Lastly, inversions are found which occur on both sex chromosomes, but at different frequencies.