Abstract
A model for the coevolution of two species in facultative symbiosis is used to investigate conditions under which species merge to form a single reproductive unit. Two traits evolve in each species, the first affecting loss of resources from an individual to its partner, and the second affecting vertical transmission of the symbiosis from one generation to the next. Initial conditions are set so that the symbiosis involves exploitation of one partner by the other and vertical transmission is very rare. It is shown that, even in the face of continuing exploitation, a stable symbiotic unit can evolve with maximum vertical transmission of the partners. Such evolution requires that eventually deaths should exceed births for both species in the free-living state, a condition which can be met if the victim, in the course of developing its defences, builds up sufficiently large costs in the free-living state. This result expands the set of initial conditions from which separate lineages can be expected to merge into symbiotic units.
Full Text
The Full Text of this article is available as a PDF (228.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cavalier-Smith T. The number of symbiotic origins of organelles. Biosystems. 1992;28(1-3):91–108. doi: 10.1016/0303-2647(92)90011-m. [DOI] [PubMed] [Google Scholar]
- Dieckmann U., Law R. The dynamical theory of coevolution: a derivation from stochastic ecological processes. J Math Biol. 1996;34(5-6):579–612. doi: 10.1007/BF02409751. [DOI] [PubMed] [Google Scholar]
- Eigen M., Schuster P. The hypercycle. A principle of natural self-organization. Part A: Emergence of the hypercycle. Naturwissenschaften. 1977 Nov;64(11):541–565. doi: 10.1007/BF00450633. [DOI] [PubMed] [Google Scholar]
- Ewald P. W. Transmission modes and evolution of the parasitism-mutualism continuum. Ann N Y Acad Sci. 1987;503:295–306. doi: 10.1111/j.1749-6632.1987.tb40616.x. [DOI] [PubMed] [Google Scholar]
- Fine P. E. Vectors and vertical transmission: an epidemiologic perspective. Ann N Y Acad Sci. 1975;266:173–194. doi: 10.1111/j.1749-6632.1975.tb35099.x. [DOI] [PubMed] [Google Scholar]
- Frank S. A. The origin of synergistic symbiosis. J Theor Biol. 1995 Oct 7;176(3):403–410. doi: 10.1006/jtbi.1995.0208. [DOI] [PubMed] [Google Scholar]
- Jeon K. W. Development of cellular dependence on infective organisms: micrurgical studies in amoebas. Science. 1972 Jun 9;176(4039):1122–1123. doi: 10.1126/science.176.4039.1122. [DOI] [PubMed] [Google Scholar]
- Marrow P., Dieckmann U., Law R. Evolutionary dynamics of predator-prey systems: an ecological perspective. J Math Biol. 1996;34(5-6):556–578. doi: 10.1007/BF02409750. [DOI] [PubMed] [Google Scholar]
- Sogin M. L. Early evolution and the origin of eukaryotes. Curr Opin Genet Dev. 1991 Dec;1(4):457–463. doi: 10.1016/s0959-437x(05)80192-3. [DOI] [PubMed] [Google Scholar]