Persistent deleterious effects of a deleterious Wolbachia infection

PLoS Negl Trop Dis. 2020 Apr 3;14(4):e0008204. doi: 10.1371/journal.pntd.0008204. eCollection 2020 Apr.

Abstract

Wolbachia are being used to reduce dengue transmission by Aedes aegypti mosquitoes around the world. To date releases have mostly involved Wolbachia strains with limited fitness effects but strains with larger fitness costs could be used to suppress mosquito populations. However, such infections are expected to evolve towards decreased deleterious effects. Here we investigate potential evolutionary changes in the wMelPop infection transferred from Drosophila melanogaster to Aedes aegypti more than ten years (~120 generations) ago. We show that most deleterious effects of this infection have persisted despite strong selection to ameliorate them. The wMelPop-PGYP infection is difficult to maintain in laboratory colonies, likely due to the persistent deleterious effects coupled with occasional maternal transmission leakage. Furthermore, female mosquitoes can be scored incorrectly as infected due to transmission of Wolbachia through mating. Infection loss in colonies was not associated with evolutionary changes in the nuclear background. These findings suggest that Wolbachia transinfections with deleterious effects may have stable phenotypes which could ensure their long-term effectiveness if released in natural populations to reduce population size.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aedes / microbiology*
  • Animals
  • Dengue / prevention & control
  • Drosophila melanogaster
  • Evolution, Molecular*
  • Female
  • Host Microbial Interactions
  • Linear Models
  • Male
  • Mosquito Control
  • Mosquito Vectors / microbiology*
  • Pest Control, Biological / methods*
  • Population Dynamics
  • Wolbachia / pathogenicity
  • Wolbachia / physiology*

Grants and funding

This work was supported by the National Health and Medical Research Council (1132412 and 1118640 to AAH, www.nhmrc.gov.au) and the Australian Research Council (DP190101877 to AAH, www.arc.gov.au). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.