A w Mel Wolbachia variant in Aedes aegypti from field‐collected Drosophila melanogaster with increased phenotypic stability under heat stress

Abstract

Summary Mosquito‐borne diseases remain a major cause of morbidity and mortality. Population replacement strategies involving the w Mel strain of Wolbachia are being used widely to control mosquito‐borne diseases. However, these strategies may be influenced by temperature because w Mel is vulnerable to heat. w Mel infections in Drosophila melanogaster are genetically diverse, but few transinfections of w Mel variants have been generated in Aedes aegypti . Here, we successfully transferred a w Mel variant (termed w MelM) originating from a field‐collected D. melanogaster into Ae. aegypti . The new w MelM variant (clade I) is genetically distinct from the original w Mel transinfection (clade III), and there are no genomic differences between w MelM in its original and transinfected host. We compared w MelM with w Mel in its effects on host fitness, temperature tolerance, Wolbachia density, vector competence, cytoplasmic incompatibility and maternal transmission under heat stress in a controlled background. w MelM showed a higher heat tolerance than w Mel, likely due to higher overall densities within the mosquito. Both w Mel variants had minimal host fitness costs, complete cytoplasmic incompatibility and maternal transmission, and dengue virus blocking under laboratory conditions. Our results highlight phenotypic differences between Wolbachia variants and w MelM shows potential as an alternative strain in areas with strong seasonal temperature fluctuations.

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