Аннотация:Many studies have shown that the associated microbiota influences the life history traits of Drosophila melanogaster. An increase in bacterial load reduces the lifespan but may increase fecundity. Paradoxically, the influence of the yeast microbiota, as a key food source for fruit flies, on life history traits is much less studied. In this work, we assessed the influence of the natural yeast microbiota, as well as individual yeast species, on lifespan, age-related dynamics of fecundity, and mortality in a control fly line and a fly line with a depleted yeast microbiota. We used Starmerella bacillaris, Zygosaccharomyces bailii, and Saccharomyces cerevisiae as yeast species for testing. We have shown that a decrease in the amount of symbiotic yeasts on the medium, on the surface of the body, or in the intestine leads to an increase in lifespan and a decrease in fecundity for flies reared on standard medium. This is consistent with the “disposable soma” hypothesis. At the same time, an increase in lifespan does not compensate for the decrease in fecundity; therefore, the decrease in the number of yeasts leads to a decrease in fitness. Inoculation of S. cerevisiae on the medium shifts the reproduction of the control flies to an earlier age, while two other yeast species increase fecundity significantly. Inoculation of S. bacillaris and S. cerevisiae (which are not typical for the microbiota of the tested fly lines) on the medium reduced the lifespan more than inoculation with Z. bailii, which is typical for the microbiota of the control line. The yeast microbiota reduced the lifespan of the D. melanogaster males more than the females. These results indicate deep coevolutionary relationships between the components of the yeast microbiota and the host organism, requiring further study within the hologenome theory of evolution.
