Full text in pdf format

Differentiation of Drosophila sendo (Isofemale line A95F3) and D. koepferae (Isofemale line B20D2): reproductive isolation, development time and polytene chromosome banding patterns

Lilian Madi-Ravazzi; Hermione Elly Melara de Campos Bicudo

Departamento de Biologia, IBILCE-UNESP, 15054-000 Sao José do Rio Preto, SP, Brasil. Scud correspondence to L.M.-R.

ABSTRACT

Drosophila sendo is considered to be a superspecies consisting of two species: D. sendo, from Brazil and D. koepferae from Argentina and Bolivia. However this probably does not express the entire evolutionary complexity of its populations. Isofemale lines A95F3 (from Brazil) and B20D2 (from Argentina), at present representing, respectively, the first and second species, were analyzed for fertility and fecundity in pair-mating intracrosses and intercrosses, as well as for development time, banding patients and asynapsis of polytene chromosomes in the isofemale lines and their hybrids.
Although variations in experimental conditions resulted in some variability in the results, in general A95F3 fertility and fecundity were lower than in B20D2. Intercrosses of A95F3 females and B20D2 males showed lower fertility and fecundity than the reciprocal crosses, following more closely characteristics of the mother strains. This is in contrast to the results obtained by Fontdevilla el al. (An. Entomol. Soc. Amer. 81: 380-385, 1988) and may be due to the different geographic origin of D. sendo strains they used in crosses to B20D2. This difference and others cited in the literature relative to aedeagus morphology, karyotype characteristics, inversion polymorphisms and reproductive isolation strongly indicate that A95F3 and D. sendo from the State of Bahia, Brazil are not a single evolutionary entity, reinforcing the idea of greater complexity of the superspecies D. serido than is known today.
The reproductive isolation mechanisms found operating between A95F3 and B20D2 were prezygotic and postzygotic, the latter included modality at the larval stage in both directions of crosses and sterility of male hybrids in intercrosses involving B20D2 females and A95F3 males. The two isofemale lines differed in egg-adult development time, which was also differently affected by culture medium composition.

Keywords: Drosophila serido; D.koepferae; reproductive isolation; development time; polytene chromosome.

REFERENCES

Atherton, D. and Gall, J. (1972). Salivary gland squashes for in situ nucleic acid hybridization studies. Drosophila Inf. Serv. 49: 131-133.

Baimai, V., Sene, EM. and Pereira, M.A.Q.R. (1983). Heterochromatin and karyotypic differentiation of some neotropical cactus breeding species of the Drosophila rep/em species group. Genetica 60: 81-91.

Bicudo, H.E.M.C. (1978). Reproductive isolation in Drosophila prosaltans (saltans group). Rev. liras. Genet. 1: 11-27.

Bizzo, N.M.V. (1983). Estudos sobre a biologia e isolamento reprodutivo em Drosophila serido. Masters Thesis. Instituto de Biociências, US P, Silo Paulo.

Demerec, M. and Kaufmann, B.P. (1945). Drosophila guide. The Lord Baltimore Press, Baltimore, Maryland.

Dobzhansk, Th. and Powell, J.R. (1975). The willistoni group of sibling species of Drosophila. In: Handbook of Genetics. Vol. 3: Invertebrates of genetic interest. (King, R.C. cd.). Plenum Publishing Corporation. New York, pp. 589-622.

Dobzhansky,Th. and Spassky, B. (1959). Drosophila paulistorumu, a cluster of species in status nascendi. Proc. Nat. Acad. Sei. (USA) 45: 419-428.

Fontdevila, A., Pla, C., I lasson, E., Wasserman, M., Sanchez, A., Naveira, II. and Ruiz, A. (1988). An. Entomol. Soc. Amer. 81: 380-385.

Guimarães, M.C. and Bicudo, I I.E.M.C. (1982). Yeast also increases the frequency of metaphases in Drosophila brain. Rev. Bras. Genet. V: 433-436.

Kircker, H.W. (1982). Ecological Genetics and Evolution. (W.T. Scanner and J.S.F. Barker, eds.). Academic Press, Austrália.

Naveira, H. and Fontdevila, A. (1985). The evolutionary history of Drosophila buzzatii. IX. High frequencies of new chromosome rearrangements induced by introgressive hybridization. Chromosoma (Berl.) 91: 87-94.

Pereira, M.A.Q.R., Vilela, C.R. and Sene, E.M. (1983). Notes on breeding and feeding sites on some speeies of the repleta group of the genus Drosophila (Diptera, Drosophilidae). Ciênc. Cult. 35: 1313-1319.

Richmond, R.C. and Dobzhansky, Th. (1976). Genetic differentiation within the Andean semiespecies of Drosophila paulistorum. Evolution 30: 746-756.

Riede, I. and Reitz, M. (1983). Study on the somatic pairing of polytene chromosomes. Chromosoma 88: 116-123.

Ruiz, A., Fontdevila, A. and Wasserman, H. (1982). The evolutionary history of Drosophila buzzatii. III.Cytogenetic relationships between two sibling species of the buzzatii cluster. Genetics 101: 503-518.

Ruiz, A., Naveira, 11. and Fontdevila, A. (1985). Tile evolutionary history of Drosophila buzzatii. V. Differential survivorship on Opuntia between D. buzzatii and D. serido. Experientia 41: 129-131.

Sene, F.M., Pereira, M.A.Q.R. and Vilela, C.R. (1982). Evolutionary aspects of cactus breeding Drosophila species in South America. p. 97-106. In: Ecological Genetics and Evolution, Academic Press, Australia. Sene, F.M., Pereira, M.A.Q.R. and Vilela, C.R. (1988). Contrasting patterns of differentiation inferred from traditional genetic markers in the process of speciat ion. Pacific Science 42: 81-88.

Silva, A.F.G. and Sene, F.M. (1991). Morphological geographic variability in Drosophila serido (Diptera, Drosophilidae). Rev. Bras. Ent. 35: 455-468.

Silva, A.P.G. (1981). Sistemática de Drosophila serido (Diptera, Drosophilidae). Ciênc. Cult. 33: 684.

Silva, A.P.G. (1983). Sistemática de Drosophila serido. Masters Thesis. Instituto de Biociências, USP, Sao Paulo.

Tadei, W.P. (1977). Estudo cromossômico, do isolamento reprodutivo e do estado-de-ser-adaptado de populações de Drosophila prosa/taus e Drosophila sultans. Doctoral Thesis. Instituto de Biociências, USP, São Paulo.

Tosi, D. (1982). Análise das inversões cromossômicas de D. serido. Masters Thesis, Instituto de Biociências, USP, São Paulo.

Tosi, D. and Sene, F.M. (1989). Further studies on chromosomal variability in the complex taxou Drosophila serido (Diptera, Drosophllidae). Rev Bras. Genet. 12: 729-745.

Vilela, C.R. and Sene, F.M. (1977). Two new neotropical species of the "repleta group" of the genus Drosophila (Diptera, Drosophilidae). Pap. Avul. Zoo!. (SP) 30: 295-299.

Wasserman, M. and Richardson, R.H. (1987). Evolution of Brazilian Drosophila mulleri complex species. Journal of Heredity 78: 282-286.