Abstract
Drosophila sechellia, endemic to the Seychelles, breeds in a single resource, Morinda citrifolia, whereas its close sympatric relative, Drosophila simulans, is a cosmopolitan generalist breeding in a great variety of resources. The effects of morinda on various fitness traits of these two species, their F1 hybrids, and reciprocal backcrosses were analyzed. Morinda fruit is highly toxic to Drosophila species, except D. sechellia. The toxicity is expressed in adults, embryos, and larvae. In embryos, early mortality is a maternally inherited trait, depending only on mother's genotype. The tolerance of D. sechellia to morinda is fully dominant in F1 hybrids. Egg production is stimulated by morinda in D. sechellia but inhibited in D. simulans; in hybrids, the inhibition observed in D. simulans is dominant. Morinda is an oviposition attractant for D. sechellia but a repellent for D. simulans; F1 hybrids and backcross individuals exhibit intermediate, approximately additive, behavior. In the field, adult flies of the two species exhibit opposite behavior in that D. sechellia is attracted to morinda and D. simulans is attracted to banana; hybrids have an intermediate behavior. These differences between the species explain why they do not hybridize in nature although living in sympatry. The various traits have different genetic bases: three or four different genes, or groups of genes, differentiate the ecological niches of the two species.
Full text
PDF




Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cariou M. L., Solignac M., Monnerot M., David J. R. Low allozyme and mtDNA variability in the island endemic species Drosophila sechellia (D. melanogaster complex). Experientia. 1990 Jan 15;46(1):101–104. doi: 10.1007/BF01955430. [DOI] [PubMed] [Google Scholar]
- Choudhary M., Singh R. S. A Comprehensive Study of Genic Variation in Natural Populations of Drosophila melanogaster. III. Variations in Genetic Structure and Their Causes between Drosophila melanogaster and Its Sibling Species Drosophila simulans. Genetics. 1987 Dec;117(4):697–710. doi: 10.1093/genetics/117.4.697. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hyytia P., Capy P., David J. R., Singh R. S. Enzymatic and quantitative variation in European and African populations of Drosophila simulans. Heredity (Edinb) 1985 Apr;54(Pt 2):209–217. doi: 10.1038/hdy.1985.28. [DOI] [PubMed] [Google Scholar]
- Jones J. S. Can genes choose habitats? Nature. 1980 Aug 21;286(5775):757–758. doi: 10.1038/286757a0. [DOI] [PubMed] [Google Scholar]
- Singh R. S. Population genetics and evolution of species related to Drosophila melanogaster. Annu Rev Genet. 1989;23:425–453. doi: 10.1146/annurev.ge.23.120189.002233. [DOI] [PubMed] [Google Scholar]
- Taylor C. E. Genetic variation in heterogeneous environments. Genetics. 1976 Aug;83(4):887–894. doi: 10.1093/genetics/83.4.887. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vouidibio J., Capy P., Defaye D., Pla E., Sandrin J., Csink A., David J. R. Short-range genetic structure of Drosophila melanogaster populations in an Afrotropical urban area and its significance. Proc Natl Acad Sci U S A. 1989 Nov;86(21):8442–8446. doi: 10.1073/pnas.86.21.8442. [DOI] [PMC free article] [PubMed] [Google Scholar]