Cytotaxonomy of Black Flies (Simuliidae)

Simulium (Chirostilbia) brunnescens (Diptera: Simuliidae) - new species from the Brazilian cerrado, Manso Dam, state of Mato Grosso, Brazil

“…The subgenus Inaequalium, for example, is known for the extreme similarity among the adults and apparently trivial differences, such as gill bifurcations or the shape of the apex of the gill are used for species identification. We agree with the literature (WHO 1978, Rothfels 1979, Crosskey 1993, Adler & Kachvorian 2001) that cytogenetics and molecular biology are promising methods to solve pending taxonomic problems in this family. Nonetheless, the differences between S. brunnescens and S. subpallidum are solid and constant in the examined populations to be considered a new species.…”

Chromosomal comparisons among and within populations of Simulium (Chirostilbia) pertinax (Diptera, Simuliidae)

“…Highly conserved areas occur in the chromosomes of some simuliid species such as in the IIIS arm of Simulium species (Rothfels 1979, Procunier 1989 or chromosomes I and III of Ectemnaspis species (Campos & Muñoz de Hoyos 1990). Since the absence of conspicuous chromosomal polymorphism is not necessarily conclusive evidence of reduced genetic variability among these populations, molecular studies could help to resolve this uncertainty.…”

Sex-linked inversions in blackflies (Diptera:Simuliidae)

“…However, the observations that the karyotypes of closely related species often differ only in the sex chromosomes (Rothfels, 1979) and only very rarely share the same differentiated sex chromosome pair (table 1) are suggestive. The process described above for the evolution of genes which interact epistatically with sex could result in changes in the sexual system such that either pre-or post-zygotic isolation developed between populations according to any of several speciation models discussed by White (1978).…”

“…Polytene chromosome studies of the Simuliidae also frequently reveal the existence of sibling species and it seems that quite often the karyotypes of such species differ only in their sex chromosomes (Rothfels, 1979). This has led to the suggestion that structural rearrangement of the sex chromosomes may be an integral part, if not the driving force in Blackfly speciation (Bedo, 1977;White, 1978).…”