Rodolfo Medellín, a protector of bats, agave and sustainable tequila

If the bat already had bad press among humans because of its link to vampires in popular imagination, the global coronavirus pandemic its reputation has worsened its reputation by the theory that this animals transmitted the virus from China.

“They have a very bad reputation worldwide, like scorpions, snakes, sharks or spiders. They are the most unjustly mistreated in the world, but, curiously, no other animal does more for human well-being and the conservation of ecosystems than they do,” biologist Roberto Medellín, an expert on bats since he was 12 years old, told El País’ Andrea Jiménez.

It is the human species that intervenes in this outlook of bats, but, principally, it is the Homo sapiens who have altered the natural cycles in which these mammals participate to maintain the balance of the ecosystem.

Bats are the only mammals that can fly, and only three of its more than thousand species feed on blood; the rest eat insects, vertebrate and invertebrate fish, fruit and nectar. For example, every million free-tailed bats eat 10 tons of insects every night in the northern border area of Mexico, Medellín reveals to El País, thus keeping corn, coffee and other food crops safe from pests that would otherwise destroy them.

And the role of so-called nectar-feeding bats in pollination of many plants is vital. These flying mammals feed on the nectar of flowers, and, in doing so, they carry pollen that fertilizes them. When bats are feeding, flowers activate the receptor organ in which the bat deposits pollen. These flowers then fertilize and produce seeds.

So the bat is also responsible for the existence of tequila. And this is where Rodrigo Medellin comes in as a defender of these animals. “His work on community ecology and on bats as indicators and as providers of environmental services such as pest control, pollination and seed dispersal has been used to justify the creation of natural protected areas or to integrate management plans. Their joint work with other colleagues on protocols for listing species at risk is now a federal law,” Medellín’s bio points out. He is a professor at the Institute of Ecology at the National Autonomous University of Mexico.

Not for nothing did naturalist and documentary filmmaker David Attenborough baptize Medellín as Bat Man.

Medellín knows well from his expertise that the existence of the blue agave, the plant that gives rise to tequila and mescal, depends on the bat species Leptonycteris yerbabuenae, L. nivalis and Mexican Choeronycteris.  These three species are the main pollinators of the agave, but the industrial processes of tequila production and, more recently, mescal threaten the natural cycle of pollination of these plants, because they prevent the flowers from coming out.

As a National Geographic in Spanish piece explains, many growers cut the flowers of the blue agave before pollination in order to increase its sugar content. According to the website of Bat Friendly — the project of which Rodrigo Medellín is co-chairman and which since 2016 has succeeded in getting 5% of the agaves in various tequila and mescal brands crops to flower –, large-scale industrial production of agave distillates requires that the raw material be harvested before the plant flowers, because otherwise the sugar needed for fermentation goes to the nectar in flowers, “and the plant is no longer good for producing tequila nor mezcal.” This “breaks the cycle of reproduction [which] in turn causes food shortages for nectar-feeding bats,” they explain.

In addition, industrial production uses agave clones, or hijuelos, which naturally grow at a short distance from the mother plant and become independent. To meet the high demand for tequila, industrials of tequila transplant the hijuelos because they grow much faster, even years before, than a pollinated agave. But, since they are clones”they have no significant genetic variation compared to the mother (…)The downside of the overexploitation of this resource is that after all they’re clones and next generation of agaves will have no significant genetic variation and no adaptation to the environment, being all the same genetically when disease or plague strike can wipe the entire population.”

That’s what happened a few years ago: a fungus and a bacteria together from a beetle plagued the blue agaves. The farmers called it “the death of the agave,” Andrea Jiménez reported for El País. According to this piece, in 2013 Rodrigo Medellín turned to the Tequila Interchange Project (TPI), an organization that had already been promoting the sustainable cultivation and marketing of agave and its liquors since 2010, to bring forward to them that bats were essential for the sick agaves to recover and be kept safe from new pests.

The piece by Jiménez says that the president of the TPI, David Suro, gave entry to Medellín to the tequila sector. Bat Friendly was then born in 2016, from a meeting between academics, producers, distillers, bottlers, marketers and bartenders

Since then many tequila producers allow agave to flower in 5% of their plantations. “They are full of food and bats visit them; it’s a historic event. That’s how things were done six generations ago,” Medellín told National Geographic en Español.

The scientists involved in the project verify that in the 5% of flowering agaves “effectively pollinate the plants, that seeds are produced and that these seeds incorporate genetic diversity,” a brief report on the project by the International Union for Conservation of Nature (IUCN) says.

Besides being bat-friendly, the tequila and mescal that comes out of it guarantee the life of the agaves. “That tequila is the only one that has a future, because it doesn’t happen like the rest of the crops: being composed of equal individuals, if one gets sick, the others will too,” Medellín told El País.

When Bat-Friendly began, they launched 300,000 bottles of tequila of five different brands, according to the IUCN. By 2019, Bat Friendly’s website lists nine brands of bat-friendly tequila and mescal and seven bars in the United States —the world’s largest consumer of tequila— where they serve them.

Photo: Bat Friendly’s website