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Updated: May 24, 2026
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Published on: October 4, 2024
Wolbachia induces male-specific mortality in the mosquito Culex pipiens (LIN strain)
1The Department of Entomology, Center for Infectious Disease Dynamics and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, United States of America. jlr54@psu.edu
Background:
Wolbachia are maternally inherited endosymbionts that infect a diverse range of invertebrates, including insects, arachnids, crustaceans and filarial nematodes. Wolbachia are responsible for causing diverse reproductive alterations in their invertebrate hosts that maximize their transmission to the next generation. Evolutionary theory suggests that due to maternal inheritance, Wolbachia should evolve toward mutualism in infected females, but strict maternal inheritance means there is no corresponding force to select for Wolbachia strains that are mutualistic in males.
Methodology/Principal Findings:
Using cohort life-table analysis, we demonstrate that in the mosquito Culex pipiens (LIN strain), Wolbachia-infected females show no fitness costs due to infection. However, Wolbachia induces up to a 30% reduction in male lifespan.
Conclusions/Significance:
These results indicate that the Wolbachia infection of the Culex pipiens LIN strain is virulent in a sex-specific manner. Under laboratory situations where mosquitoes generally mate at young ages, Wolbachia strains that reduce male survival could evolve by drift because increased mortality in older males is not a significant selective force.
Insights
Wolbachia bacteria harm male mosquitoes, reducing their lifespan by up to 30% without affecting females. This sex-specific virulence in Culex pipiens suggests Wolbachia can evolve due to reduced male survival, impacting host populations.
Area of Science:
- Microbiology
- Evolutionary Biology
- Entomology
Background:
- Wolbachia are maternally inherited endosymbionts found in various invertebrates.
- They manipulate host reproduction to enhance their own transmission.
- Maternal inheritance favors mutualism in females but not males.
Purpose of the Study:
- To investigate the fitness effects of Wolbachia infection in the mosquito Culex pipiens.
- To determine if Wolbachia infection impacts male and female mosquito lifespan differently.
Main Methods:
- Cohort life-table analysis was used.
- The study focused on the Culex pipiens LIN strain.
Main Results:
- Wolbachia infection did not impose fitness costs on infected female mosquitoes.
- Wolbachia infection led to a significant reduction in male mosquito lifespan, up to 30%.
Conclusions:
- Wolbachia infection in Culex pipiens exhibits sex-specific virulence.
- Reduced male survival may be tolerated by Wolbachia strains due to drift, especially in laboratory settings with early mating ages.
