Abstract
Larval populations of the morphologically distinct species Simulium ornatipes and S. neornatipes and a subspecies of the former, S. ornatipes norfolkense, were analysed using polytene chromosome cytology. Fixed inversion differences, distinct differentiated sex chromosomes and unique arrays of chromosomal polymorphisms reveal two sibling species, S. ornatipes A and B, within S. ornatipes, and two, S. neornatipes 1 and 2, within S. neornatipes. Chromosomally S. ornatipes norfolkense is similar to S. ornatipes A. An unprecedented level of shared inversion polymorphism is shown by S. ornatipes A and B indicating a very close relationship between them. While it may be postulated that such a situation has arisen by independent origin of the shared inversions within each species, or by introgression of these rearrangements between the two species, it is concluded that the shared polymorphisms in fact originate from a common ancestor. Within the four chromosomally defined species, differentiated sex chromosome systems occur which may involve any of the three chromosome pairs. Simulium ornatipes A is particularly interesting because there are indications that it may be polymorphic for differentiated sex chromosomes on two different elements and that it may also share a sex chromosome marker with S. ornatipes B, a unique situation in the Simuliidae. The evolution of sex chromosome systems in the four species is compared with that of other Simulids and its intimate connection with speciation emphasised. Finally the data on fixed inversions, differentiated sex chromosomes and shared polymorphisms is used to construct a phylogeny of the four species outlining their patterns of speciation.
Similar content being viewed by others
References
Basrur, P.K.: The salivary gland chromosomes of seven segregates of Prosimulium (Diptera:Simuliidae) with a transformed centromere. Canad. J. Zool. 37, 527–570 (1959)
Basrur, P. K.: The salivary gland chromosomes of seven species of Prosimulium (Diptera:Simuliidae) from Alaska and British Columbia. Canad. J. Zool. 40, 1019–1033 (1962)
Basrur, V.R., Rothfels, K.H.: Triploidy in naturnal populations of the black fly Cnephia mutata (Mallock). Canad. J. Zool. 37, 571–589 (1959)
Bedo, D.G.: Polytene chromosomes of three species of blackflies in the Simulium pictipes group (Diptera:Simuliidae). Canad. J. Zool. 53, 1147–1167 (1975a)
Bedo, D.G.: C banding in polytene chromosomes of Simulium ornatipes and S. melatum (Diptera: Simuliidae). Chromosoma (Berl.) 51, 291–300 (1975b)
Bedo, D.G.: Polytene chromosomes in pupal and adult blackflies (Diptera:Simuliidae). Chromosoma (Berl.) 57, 387–396 (1976)
Beermann, W.: Geschlechtsbestimmung und Evolution der genetischen Y-chromosomen bei Chironomus. Biol. Zbl. 74, 525–544 (1955)
Carson, H.L.: Patterns of speciation in Hawaiian Drosophila inferred from ancient chromosomal polymorphism. In: Genetic mechanisms of speciation in insects (M.J.D. White, Ed.) p. 81–93. Sydney: Australia and New Zealand Book Company 1974
Carson, H.L.: The genetics of speciation at the diploid level. Amer. Naturalist 109, 83–92 (1975)
Carson, H.L., Hardy, D.E., Spieth, H.T., Stone, W.S.: The evolutionary biology of the Hawaiian Drosophilidae. In: Essays in Evolution and genetics in honour of Theodosius Dobzhansky (M.K. Hecht and W.C. Steere, eds.), pp. 457–543. New York: Appleton Century Crofts 1970
Carson, H.L., Nair, P.S., Sene, F.M.: Drosophila hybrids in nature: proof of gene exchange between sympatric species. Science 189, 806–807 (1975)
Colbo, M.H.: Four new species of Simulium Latreille (Diptera:Simuliidae) from Australia. J. Aust. Ent. Soc. 15, 253–269 (1976)
Crosskey, R.W.: The classification of Simulium Latreille (Diptera:Simuliidae) from Australia, New Guinea and the Western Pacific. J. nat. Hist. 1, 23–51 (1967)
Crosskey, R.W.: A reclassification of the Simuliidae (Diptera) of Africa and its islands. Bull. Brit. Mus. nat. Hist. (Ent.) 14, 1–195 (1969)
Dobzhansky, Th.: Is there gene exchange between Drosophila pseudoobscura and Drosophila persimilis in their natural havitats? Amer. Naturalist 107, 312–314 (1973)
Dobzhansky, Th., Epling, C.: Contributions to the genetics, taxonomy and ecology of Drosophila pseudoobscura and its relatives. Publ. Carnegie Inst. 554, 1–183 (1944)
Dumbleton, L.J.: The classification and distribution of the Simuliidae (Diptera) with particular reference to the genus Austrosimulium. New Zealand J. Sci. 6, 320–357 (1963)
Dumbleton, L.J.: New Simuliidae (Diptera) from New Caledonia and Norfolk Island. New Zealand J. Sci. 12, 213–222 (1969)
Dunbar, R.W.: The salivary gland chromosomes of two sibling species of black flies included in Eusimulium aureum Fries. Canad. J. Zool. 36, 23–44 (1958)
Dunbar, R.W.: The salivary gland chromosomes of seven forms of black flies included in Eusimulium aureum Fries. Canad. J. Zool. 37, 495–525 (1959)
Dunbar, R.W.: The salivary gland chromosomes of six closely related black flies near Eusimulium congareenarum (Diptera:Simuliidae). Canad. J. Zool. 45, 377–396 (1967)
Dunbar, R.W.: Nine cytological segregates in the Simulium damnosum complex (Diptera:Simuliidae). Bull. Wld Hlth. Org. 40, 974–979 (1969)
Landau, R.: Four forms of Simulium tuberosum (Lundstr.) in Southern Ontario: A salivary gland chromosome study. Canad. J. Zool. 40, 921–939 (1962)
Mackerras, I.M.: The zoogeography of the Diptera. Aust. J. Sci. 12, 157–161 (1950)
Mackerras, M.J., Mackerras, I.M.: Notes on Australian Simuliidae (Diptera). IV. Proc. Linn. Soc. N.S.W. 80, 105–112 (1955)
Madahar, D.P.: The salivary gland chromosomes of seven taxa in the subgenus Stegopterna (Diptera, Simuliidae, Cnephia). Canad. J. Zool. 47, 115–119 (1969)
Ottonen, P.O.: The salivary gland chromosomes of six species in the IIIS-1 group of Prosimulium Roub. (Diptera:Simuliidae). Canad. J. Zool. 44, 677–701 (1966)
Ottonen, P.O., Nambiar, R.: The salivary gland chromosomes of Prosimulium multidentatum Twinn and three forms included in Prosimulium magnum (Dyar and Shannon) (Diptera: Simuliidae). Canad. J. Zool. 47, 943–949 (1969)
Pasternak, J.: Chromosome polymorphism in the blackfly Simulium vittatum (Zett.). Canad. J. Zool. 42, 135–158 (1964)
Procunier, W.S.: A cytological study of two closely related blackfly species: Cnephia dacotensis and Cnephia ornithophilia (Diptera:Simuliidae). Canad. J. Zool. 53, 1622–1637 (1975)
Rothfels, K.H.: Black flies: siblings, sex, and species grouping. J. Hered. 47, 113–122 (1956)
Rothfels, K.H., Dunbar, R.W.: The salivary gland chromosomes of the black fly Simulium vittatum Zett. Canad. J. Zool. 31, 226–241 (1953)
Rothfels, K.H., Freeman, M.: The salivary gland chromosomes of three North American species of Twinnia (Diptera:Simuliidae). Canad. J. Zool. 44, 937–945 (1966)
Rothfels, K.H., Mason, G.F.: Achiasmate meiosis and centromere shift in Eusimulium aureum (Diptera-Simuliidae). Chromosoma (Berl.) 51, 111–124 (1975)
Skuse, F.A.A.: Diptera of Australia. Nematocera — Supplement II. Proc. Linn. Soc. N.S.W. 15, 595–640 (1890)
Smart, J., Clifford, E.A.: Simuliidae (Diptera) of the territory of Papua and New Guinea. Pacific Insects 7, 505–619 (1965)
Vajime, C.G., Dunbar, R.W.: Chromosomal identification of eight species of the Subgenus Edwardsellum near and including Simulium (Edwardsellum) damnosum Theobald (Diptera:Simuliidae). Tropenmed. Parasit. 26, 111–138 (1975)
Wasserman, M.: Cytology and phylogeny of Drosophila. Amer. Naturalist 97, 333–352 (1963)
Wharton, R.H.: Simuliidae (Diptera, Nematocera) from New Guinea, with the description of one new species. Proc. Linn. Soc. N.S.W. 72, 357–366 (1948)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bedo, D.G. Cytogenetics and evolution of Simulium ornatipes skuse (Diptera:Simuliidae) I. Sibling speciation. Chromosoma 64, 37–65 (1977). https://doi.org/10.1007/BF00292888
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00292888