Population Dynamics of the Wolbachia Infection Causing Cytoplasmic Incompatibility in Drosophila melanogaster

Corresponding author: Ary A. Hoffmann, School of Genetics and Human Variation, La Trobe Univeresity, Bundoora, Victoria 3083, Australia, genaah{at}gen.latrobe.edu.au (E-mail).

Communicating editor: J. HEY

Field populations of Drosophila melanogaster are often infected with Wolbachia, a vertically transmitted microorganism. Under laboratory conditions the infection causes partial incompatibility in crosses between infected males and uninfected females. Here we examine factors influencing the distribution of the infection in natural populations. We show that the level of incompatibility under field conditions was much weaker than in the laboratory. The infection was not transmitted with complete fidelity under field conditions, while field males did not transmit the infection to uninfected females and Wolbachia did not influence sperm competition. There was no association between field fitness as measured by fluctuating asymmetry and the infection status of adults. Infected field females were smaller than uninfecteds in some collections from a subtropical location, but not in other collections from the same location. Laboratory cage studies showed that the infection did not change in frequency when populations were maintained at a low larval density, but it decreased in frequency at a high larval density. Monitoring of infection frequencies in natural populations indicated stable frequencies in some populations but marked fluctuations in others. Simple models suggest that the infection probably provides a fitness benefit for the host in order to persist in populations. The exact nature of this benefit remains elusive.

This article has been cited by other articles:

				S. J. Perlman, S. E. Kelly, and M. S. Hunter Population Biology of Cytoplasmic Incompatibility: Maintenance and Spread of Cardinium Symbionts in a Parasitic Wasp Genetics, February 1, 2008; 178(2): 1003 - 1011. [Abstract] [Full Text] [PDF]

				S. Goto, H. Anbutsu, and T. Fukatsu Asymmetrical Interactions between Wolbachia and Spiroplasma Endosymbionts Coexisting in the Same Insect Host. Appl. Envir. Microbiol., July 1, 2006; 72(7): 4805 - 4810. [Abstract] [Full Text] [PDF]

				M. E. Clark, C. L. Anderson, J. Cande, and T. L. Karr Widespread Prevalence of Wolbachia in Laboratory Stocks and the Implications for Drosophila Research Genetics, August 1, 2005; 170(4): 1667 - 1675. [Abstract] [Full Text] [PDF]

				D. D. Shoemaker, K. A. Dyer, M. Ahrens, K. McAbee, and J. Jaenike Decreased Diversity but Increased Substitution Rate in Host mtDNA as a Consequence of Wolbachia Endosymbiont Infection Genetics, December 1, 2004; 168(4): 2049 - 2058. [Abstract] [Full Text] [PDF]

				L. Mouton, F. Dedeine, H. Henri, M. Bouletreau, N. Profizi, and F. Vavre Virulence, Multiple Infections and Regulation of Symbiotic Population in the Wolbachia-Asobara tabida Symbiosis Genetics, September 1, 2004; 168(1): 181 - 189. [Abstract] [Full Text] [PDF]

				M. D. Dean, K. J. Ballard, A. Glass, and J. W. O. Ballard Influence of Two Wolbachia Strains on Population Structure of East African Drosophila simulans Genetics, December 1, 2003; 165(4): 1959 - 1969. [Abstract] [Full Text] [PDF]

				J. L. Rasgon and T. W. Scott Wolbachia and Cytoplasmic Incompatibility in the California Culex pipiens Mosquito Species Complex: Parameter Estimates and Infection Dynamics in Natural Populations Genetics, December 1, 2003; 165(4): 2029 - 2038. [Abstract] [Full Text] [PDF]

				K. T. Reynolds, L. J. Thomson, and A. A. Hoffmann The Effects of Host Age, Host Nuclear Background and Temperature on Phenotypic Effects of the Virulent Wolbachia Strain popcorn in Drosophila melanogaster Genetics, July 1, 2003; 164(3): 1027 - 1034. [Abstract] [Full Text] [PDF]

				D. M. Rand, A. G. Clark, and L. M. Kann Sexually Antagonistic Cytonuclear Fitness Interactions in Drosophila melanogaster Genetics, September 1, 2001; 159(1): 173 - 187. [Abstract] [Full Text] [PDF]

				R. R. Snook, S. Y. Cleland, M. F. Wolfner, and T. L. Karr Offsetting Effects of Wolbachia Infection and Heat Shock on Sperm Production in Drosophila simulans: Analyses of Fecundity, Fertility and Accessory Gland Proteins Genetics, May 1, 2000; 155(1): 167 - 178. [Abstract] [Full Text]