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Maintaining Aedes aegypti Mosquitoes Infected with Wolbachia
Published on: August 14, 2017
Wolbachia infection lowers fertile sperm transfer in a moth
Z Lewis1, F E Champion de Crespigny, S M Sait
1Centre for Ecology and Conservation, Biosciences, University of Exeter, Cornwall Campus, Penryn, UK.
Abstract:
The endosymbiotic bacterium Wolbachia pipientis manipulates host reproduction by rendering infected males reproductively incompatible with uninfected females (cytoplasmic incompatibility; CI). CI is believed to occur as a result of Wolbachia-induced modifications to sperm during maturation, which prevent infected sperm from initiating successful zygote development when fertilizing uninfected females' eggs. However, the mechanism by which CI occurs has been little studied outside the genus Drosophila. Here, we show that in the sperm heteromorphic Mediterranean flour moth, Ephestia kuehniella, infected males transfer fewer fertile sperm at mating than uninfected males. In contrast, non-fertile apyrene sperm are not affected. This indicates that Wolbachia may only affect fertile sperm production and highlights the potential of the Lepidoptera as a model for examining the mechanism by which Wolbachia induces CI in insects.
Insights
Wolbachia bacteria cause reproductive incompatibility in insects. In Ephestia kuehniella moths, Wolbachia infection reduces the number of fertile sperm transferred by males, offering a new model to study this phenomenon.
Area of Science:
- Microbiology
- Insect Reproduction
- Genetics
Background:
- Wolbachia pipientis is an endosymbiotic bacterium known to manipulate host reproduction through cytoplasmic incompatibility (CI).
- CI is characterized by reproductive incompatibility between infected males and uninfected females, attributed to sperm modifications during maturation.
- The precise mechanisms underlying CI remain largely unelucidated, particularly outside the genus Drosophila.
Purpose of the Study:
- To investigate the mechanism of Wolbachia-induced CI in the Mediterranean flour moth, Ephestia kuehniella.
- To determine if Wolbachia affects the number of fertile sperm transferred during mating in E. kuehniella.
Main Methods:
- Comparative analysis of sperm transfer in mated E. kuehniella males, comparing Wolbachia-infected and uninfected individuals.
- Quantification of fertile and non-fertile (apyrene) sperm transferred at mating.
Main Results:
- Males infected with Wolbachia transferred significantly fewer fertile sperm compared to uninfected males.
- The number of non-fertile apyrene sperm transferred was not affected by Wolbachia infection.
- This suggests Wolbachia specifically impacts fertile sperm production or viability.
Conclusions:
- Wolbachia infection in E. kuehniella selectively reduces fertile sperm count, providing a potential mechanism for CI.
- The Lepidoptera, specifically E. kuehniella, presents a promising model system for further research into the molecular basis of Wolbachia-induced CI.
- These findings contribute to understanding host-microbe interactions and reproductive manipulation in insects.
