Historic museum samples provide evidence for a recent replacement ofWolbachiatypes in EuropeanDrosophila melanogaster

Abstract

AbstractWolbachiais one of the most common bacterial endosymbionts, which is frequently found in numerous arthropods and nematode taxa.Wolbachiainfections can have a strong influence on the evolutionary dynamics of their hosts since these bacteria are reproductive manipulators that affect the fitness and life history of their host species for their own benefit. Host-symbiont interactions withWolbachiaare perhaps best studied in the model organismDrosophila melanogaster, which is naturally infected with five different types among which wMel and wMelCS are the most frequent ones. Comparisons of infection types between natural flies and long-term lab stocks have previously indicated that wMelCS represents the ancestral type, which was only very recently replaced by the nowadays dominant wMel in most natural populations. In this study, we took advantage of recently sequenced museum specimens ofD. melanogasterthat have been collected 90-200 years ago in Northern Europe to test this hypothesis. Our comparison to contemporaryWolbachiasamples provides compelling support for the replacement hypothesis and identifies potential infections with yet unknownWolbachiatypes of supergroup B. Our analyses show that sequencing data from historic museum specimens and their bycatch are an emerging and unprecedented resource to address fundamental questions about evolutionary dynamics in host-symbiont interactions.