title: Social wasps are a Saccharomyces mating nest.
abstract: The reproductive ecology of Saccharomyces cerevisiae is still largely unknown. Recent evidence of interspecific hybridization, high levels of strain heterozygosity, and prion transmission suggest that outbreeding occurs frequently in yeasts. Nevertheless, the place where yeasts mate and recombine in the wild has not been identified. We found that the intestine of social wasps hosts highly outbred S. cerevisiae strains as well as a rare S. cerevisiae×S. paradoxus hybrid. We show that the intestine of Polistes dominula social wasps favors the mating of S. cerevisiae strains among themselves and with S. paradoxus cells by providing a succession of environmental conditions prompting cell sporulation and spores germination. In addition, we prove that heterospecific mating is the only option for European S. paradoxus strains to survive in the gut. Taken together, these findings unveil the best hidden secret of yeast ecology, introducing the insect gut as an environmental alcove in which crosses occur, maintaining and generating the diversity of the ascomycetes.
authors.affiliation: Centre for Research and Innovation, Fondazione Edmund Mach, 38010 Trento, Italy;
authors.forename: Irene
authors.initials: I
authors.lastname: Stefanini
authors.affiliation: Institut de Biologia Evolutiva, Consejo Superior de Investigaciones Científicas-Universitat Pompeu Fabra, ES-08003 Barcelona, Spain;
authors.forename: Leonardo
authors.initials: L
authors.lastname: Dapporto
authors.affiliation: Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay;
authors.forename: Luisa
authors.initials: L
authors.lastname: Berná
authors.affiliation: Department of Biology, University of Florence, 50019 Florence, Italy;
authors.forename: Mario
authors.initials: M
authors.lastname: Polsinelli
authors.affiliation: Department of Biology, University of Florence, 50019 Florence, Italy; Centro di Servizi di Spettromeria di Massa, University of Florence, 50100 Florence, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Turillazzi
authors.affiliation: Centre for Research and Innovation, Fondazione Edmund Mach, 38010 Trento, Italy; Department of Biology, University of Florence, 50019 Florence, Italy; duccio.cavalieri@unifi.it.
authors.forename: Duccio
authors.initials: D
authors.lastname: Cavalieri
mesh_terms: D000818:Animals; D044822:Biodiversity; D003433:Crosses, Genetic; D000069196:Gastrointestinal Microbiome; D012098:Reproduction / Q000235:genetics / Q000502:physiology; D012440:Saccharomyces / Q000235:genetics* / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology; D013172:Spores, Fungal / Q000235:genetics / Q000502:physiology; D014863:Wasps / Q000382:microbiology*
keywords: Saccharomyces cerevisiae; Saccharomyces paradoxus; hybrids; social wasps; yeasts