title: Aphid protected from pathogen by endosymbiont.
abstract: Aphids are associated with several facultative bacterial endosymbionts that may influence their interactions with other organisms. We show here that one of the three most common facultative symbionts of pea aphid (Acyrthosiphon pisum), the bacterium Regiella insecticola, has a major effect on host resistance to a fungal pathogen. Experimental establishment of the bacterium in uninfected aphid clones led to higher survival after fungal attack. The bacteria also increased the aphid's inclusive fitness, because the presence of the symbiont reduced the probability of fungal sporulation on aphid cadavers, hence lowering the rate of transmission of the disease to nearby related aphids.
authors.affiliation: Natural Environment Research Council Centre for Population Biology, Division of Biology, Imperial College London, Silwood Park Campus, Ascot, Berks, SL5 7PY, UK.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Scarborough
authors.forename: Julia
authors.initials: J
authors.lastname: Ferrari
authors.forename: H C J
authors.initials: HC
authors.lastname: Godfray
mesh_terms: D000818:Animals; D001042:Aphids / Q000382:microbiology* / Q000502:physiology; D004755:Enterobacteriaceae / Q000235:genetics / Q000502:physiology*; D020091:Entomophthorales / Q000472:pathogenicity / Q000502:physiology*; D008969:Molecular Sequence Data; D013172:Spores, Fungal / Q000502:physiology; D013559:Symbiosis