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Updated: Mar 19, 2026
Wolbachia Bacterial Infection in Drosophila
Published on: February 25, 2007
Tropical Drosophila pandora carry Wolbachia infections causing cytoplasmic incompatibility or male killing
Kelly M Richardson1, Michele Schiffer1, Philippa C Griffin1
1School of BioSciences, Bio21 Institute, The University of Melbourne, Victoria, 3010, Australia.
Abstract:
Wolbachia infections have been described in several Drosophila species, but relatively few have been assessed for phenotypic effects. Cytoplasmic incompatibility (CI) is the most common phenotypic effect that has been detected, while some infections cause male killing or feminization, and many Wolbachia infections have few host effects. Here, we describe two new infections in a recently described species, Drosophila pandora, one of which causes near-complete CI and near-perfect maternal transmission (the "CI" strain). The other infection is a male killer (the "MK" strain), which we confirm by observing reinitiation of male production following tetracycline treatment. No incompatibility was detected in crosses between CI strain males and MK strain females, and rare MK males do not cause CI. Molecular analyses indicate that the CI and MK infections are distantly related and the CI infection is closely related to the wRi infection of Drosophila simulans. Two population surveys indicate that all individuals are infected with Wolbachia, but the MK infection is uncommon. Given patterns of incompatibility among the strains, the infection dynamics is expected to be governed by the relative fitness of the females, suggesting that the CI infection should have a higher fitness. This was evidenced by changes in infection frequencies and sex ratios in population cages initiated at different starting frequencies of the infections.
Insights
Two new Wolbachia infections in Drosophila pandora were identified, one causing cytoplasmic incompatibility (CI) and the other male killing. These findings reveal complex Wolbachia-host interactions and infection dynamics.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genetics
Background:
- Wolbachia are intracellular bacteria known to infect various insect species.
- Phenotypic effects of Wolbachia, such as cytoplasmic incompatibility (CI) and male killing, vary significantly among hosts.
- Drosophila pandora is a recently described species with limited prior research on Wolbachia infections.
Purpose of the Study:
- To characterize novel Wolbachia infections in Drosophila pandora.
- To investigate the phenotypic effects and population dynamics of these new infections.
- To understand the evolutionary implications of Wolbachia-host interactions in this species.
Main Methods:
- Description of two new Wolbachia strains in Drosophila pandora: a CI-inducing strain and a male-killing (MK) strain.
- Confirmation of male killing through tetracycline treatment and observation of male production reinitiation.
- Molecular analyses to determine the phylogenetic relationship of the new Wolbachia strains.
- Population surveys and experimental population cage studies to assess infection frequencies and dynamics.
Main Results:
- Identification of a Drosophila pandora strain causing near-complete cytoplasmic incompatibility (CI) with high maternal transmission.
- Discovery of a distinct male-killing (MK) Wolbachia strain in Drosophila pandora.
- Molecular data indicate the CI and MK strains are distantly related, with the CI strain closely related to wRi in Drosophila simulans.
- Population studies showed MK infections are uncommon, and infection frequencies shifted in population cages, suggesting differential female fitness.
Conclusions:
- Drosophila pandora harbors diverse Wolbachia strains with significant phenotypic effects.
- The observed infection dynamics are likely driven by the relative fitness of females infected with different Wolbachia strains.
- These findings contribute to understanding Wolbachia-induced reproductive manipulations and their impact on host population genetics.
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