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Wolbachia Bacterial Infection in Drosophila
Published on: February 25, 2007
Wolbachia Infection in a Natural Parasitoid Wasp Population
Anne Duplouy1, Christelle Couchoux2, Ilkka Hanski1
1University of Helsinki, Metapopulation Research Centre, Department of Biosciences, P.O. Box 65, FI-00014, Helsinki, Finland.
Abstract:
The maternally transmitted bacterium Wolbachia pipientis is well known for spreading and persisting in insect populations through manipulation of the fitness of its host. Here, we identify three new Wolbachia pipientis strains, wHho, wHho2 and wHho3, infecting Hyposoter horticola, a specialist wasp parasitoid of the Glanville fritillary butterfly. The wHho strain (ST435) infects about 50% of the individuals in the Åland islands in Finland, with a different infection rate in the two mitochondrial (COI) haplotypes of the wasp. The vertical transmission rate of Wolbachia is imperfect, and lower in the haplotype with lower infection rate, suggesting a fitness trade-off. We found no association of the wHho infection with fecundity, longevity or dispersal ability of the parasitoid host. However, preliminary results convey spatial associations between Wolbachia infection, host mitochondrial haplotype and parasitism of H. horticola by its hyperparasitoid, Mesochorus cf. stigmaticus. We discuss the possibility that Wolbachia infection protects H. horticola against hyperparasitism.
Insights
Three new Wolbachia pipientis strains were identified in the Hyposoter horticola wasp. Wolbachia infection may offer protection against hyperparasitism, despite imperfect transmission and potential fitness trade-offs.
Area of Science:
- Bacteriology
- Insect Pathology
- Evolutionary Biology
Background:
- Wolbachia pipientis is a maternally transmitted bacterium known to manipulate host fitness in insect populations.
- Hyposoter horticola is a specialist wasp parasitoid of the Glanville fritillary butterfly.
Purpose of the Study:
- To identify new Wolbachia pipientis strains infecting H. horticola.
- To investigate the infection dynamics, transmission rates, and fitness effects of Wolbachia in H. horticola.
- To explore the potential role of Wolbachia in protecting H. horticola against hyperparasitism.
Main Methods:
- Identification of new Wolbachia pipientis strains (wHho, wHho2, wHho3) using molecular techniques.
- Assessment of Wolbachia infection rates in different mitochondrial (COI) haplotypes of H. horticola.
- Evaluation of vertical transmission rates and fitness parameters (fecundity, longevity, dispersal).
- Spatial analysis of Wolbachia infection, host haplotypes, and hyperparasitism by Mesochorus cf. stigmaticus.
Main Results:
- Three new Wolbachia strains (wHho, wHho2, wHho3) were identified in H. horticola.
- The wHho strain (ST435) infected approximately 50% of wasps in the Åland islands, with varying rates across two COI haplotypes.
- Imperfect vertical transmission was observed, being lower in the less infected haplotype, suggesting a fitness trade-off.
- No significant association was found between wHho infection and host fecundity, longevity, or dispersal.
- Preliminary spatial associations suggest Wolbachia infection might protect H. horticola against hyperparasitism.
Conclusions:
- New Wolbachia strains have been discovered in the parasitoid wasp H. horticola.
- Wolbachia infection dynamics in H. horticola are influenced by host mitochondrial haplotypes and exhibit imperfect vertical transmission.
- Wolbachia infection in H. horticola may confer protection against hyperparasitism by Mesochorus cf. stigmaticus.
