Stop killing wasps, they offer you wine !

It seems that one day Albert Einstein would have said : "If the bee were to disappear from the face of the globe, the man would only have four years to live ". Although we have no way of knowing if this sentence is from him or not, at least it has the merit of being clear : without bees, more human life. From now on, we can also say "If the wasp disappeared from the face of the globe, viticulture would only have four years to live ".

Today, we know that wasps carry the weight of viticulture on their little shoulders. Fungi living on grapes, and particularly Saccharomyces cerevisiae, are different from place to place and cause noticeable flavor nuances in the fruit. Saccharomyces cerevisiae is no stranger, it is involved in the wine making process. Remember, a brief had been written about this mushroom in " The role of terroir called into question ".

"If the wasp disappeared from the face of the globe, the wine would only be a shadow of itself "- it's scary, no ? —

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The wasp plays an essential role in wine

We already knew since 2012 thanks to Italian and French researchers how fermentation yeasts could be found on the skin of grapes. Wasps, and more precisely their digestive system, harbor these yeasts. They are transmitted to their offspring and are dispersed in nature.

The indigenous or selected yeasts used for fermentation find their origin on the skin of the grapes. Yet, when the grape is not ripe, it hardly contains yeasts. These cannot move in the air and therefore need a vector to spread. But which one ?

The University of Florence and INRA in Montpellier have looked into the question and according to them wasps and hornets are real niches for yeasts, which contribute to their dispersal in nature and to the maintenance of their diversity. According to the researchers, the wasp was an ideal candidate to play this role of “carrier”. During his hibernation, it lodges the yeasts in its intestine for many months. To feed his offspring, the wasp regurgitates its food and thereby transmits the yeast it has retained. The yeast consumed by a wasp in the fall can therefore remain in its swarm until the following summer and land on a berry..

By dissecting several wasps caught in the Italian vineyard in spring, in summer and autumn, researchers have discovered 17 different strains of Saccharomyces cerevisiae - aussi called baker's yeast - in their gut. They then fed wasps with these yeasts, then they stayed in hibernation for 3 months, and finally let them build their nests and feed their larvae. They found strains of yeast in the intestines of the larvae. However, many strains identified in wasps and larvae are strains commonly found on grapes.

The wasp has become a full-fledged factor in the typicity of wine.

A new revelation

A new publication from the National Academy of Sciences of the United States of America, shows that the wasp plays a much bigger role than previously thought. This is due to recombinations and the creation of hybrids between yeasts in the intestines of the insect during the period of hibernation.. More particularly between Saccharomyces cerevisiae, Saccharomyces paradoxus and other wild yeasts. Wasps promote yeast biodiversity and therefore flavors.

The wine therefore has regional differences in flavor influenced by their microbes., including yeasts. According to Dr Cavalieri, who leads Florence's team of scientists on the subject, “Maintaining this specificity requires maintaining the uniqueness of microbial communities”. “We wage chemical warfare against insects, all over, but our results are mainly used to say that if we continue to kill the wasps, we will lose a fundamental part of the ecological cycle”. The research team is now investigating whether a similar process is occurring in other insects, like ants.

The relationship between wasp and yeast is essential for wines, liqueurs, and beers. Wasp, considered a pest, may actually have incredible relevance, in terms of commercial and industrial value. It is this which contributes to the diversity of the senses within the same grape varieties.

Jean-Nicolas Mouretin