Bats give French winegrowers a helping hand in moth war

A study commissioned by the wine industry committee of Bordeaux, published Tuesday, found that bats were observed swooping to hunt more often towards vines where the bugs were present — meaning they could potentially be used as a natural pesticide.

A genetic analysis of the bat droppings showed they were indeed eating the moths rather than other insects.

“For the first time these results show in a formal way the capacity of bats to feed themselves on grapevine moths and cochylis moths,” the group said in a statement.

The study was carried out by France’s Animal Protection League and Bird Protection League, along with the consultancy Eliomys and the National Institute for Agricultural Research (INRA).

It observed bat activity over 23 plots of land in the winegrowing Gironde region of southwest France around Bordeaux between May and October 2017.

Yohann Charbonnier of the Bird Protection League said the conservation groups had been surprised to find as many of 19 of the 22 local bat breeds feasting on the grape-loving moths.

“We weren’t expecting so many species of bats to be frequenting the vines, which were not previously known for their biodiversity,” he told AFP.

He noted, however, that bats still appear to prefer hunting in more natural environments such as hedgerows.

The study could lead the way for vineyards to look at encouraging bats to hunt there, to allow winegrowers to reduce their pesticide use.

Currently, growers faced with an infestation have no choice but to spray their vines with chemicals.

But Charbonnier said another study would be needed to determine “whether the bats eat enough of the pests to allow reduced use of pesticides”.