43rd ANNUAL DROSOPHILA RESEARCH CONFERENCE
April 10-14, 2002

PROGRAM AND ABSTRACT VOLUME
Workshop Abstract

12W
From parasite to mutualist: Wolbachia infections that increase longevity and egg production in D. melanogaster. A. Fry, M. Palmer, D. Rand. Department of Ecology and Evolutionary Biology, Brown University, Providence, RI.

The maternally inherited bacterium Wolbachia is traditionally viewed as a reproductive parasite that manipulates host reproduction to enhance its own transmission. In Drosophila simulans this is illustrated by cytoplasmic incompatibility (CI): uninfected females have reduced fecundity when mated to infected males, but infected females have essentially normal fecundity in most matings. Wolbachia is thus maintained by the relative disadvantage of uninfected females. Despite the close evolutionary relationship of D. melanogaster and D. simulans, Wolbachia exhibits little or no CI in D. melanogaster. Without any obvious parasitic mechanism to maintain Wolbachia infections, the persistence of Wolbachia in melanogaster has been a paradox. Here we show that wild strains of melanogaster carrying Wolbachia have significantly greater longevity and lifetime fecundity than when the strain is cleared of Wolbachia using tetracycline. We have identified a strain with no such effect, and other strains with weak detrimental effects of Wolbachia on longevity and fecundity. Control experiments indicate that tetracycline treatment is not the source of these effects. Overall, there is a very significant host-by-Wolbachia interaction for longevity. We suggest that the Wolbachia infection in melanogaster is facultatively mutualistic and provides a great model for the analysis of an evolutionary transition from parasite to mutualist. Preliminary analyses of expression profiles in infected and uninfected strains will be discussed.