For Akito Kawahara and his colleagues, some pictures of soft were well deserved after a long day of butterfly catching in Mexico’s Yucatan Peninsula four years ago. But just because the booze was on the table didn’t mean the job was over.
Kawahara recalls someone mentioning that a bottle of mezcal at the bar contained one of the infamous tequila worms. When the team asked the bartender about the worm for further verification, “he thought we were crazy,” says Kawahara, a lepidopterist (a person who studies moths and butterflies) at the University of Florida.
Yet a quick internet search revealed that the species of the tequila worm is not entirely clear – although its existence is fairly common knowledge among the drinking public. “There was this mystery among the scientific community about what it actually was,” says Kawahara.
Although the worm did not look like a moth larva, it was probably the larva of something; maybe a beetle or a fly, the team initially thought. Purely in the interest of science, the researchers brought home several bottles of mekal from their expedition to the peninsula and sequenced the worms’ DNA.
Origin of the Tequila Worm
The name “tequila worm” is actually something of a misnomer. Tequila is very similar to mezcal, but the former is made only from blue agave plants mainly in and around Tequila, a city that lies between the coast of Puerto Vallarta and Guadalajara, the second most populous city in Mexico.
The famous worm is mostly found in mezcal, not tequila. But even with mezcal, not every bottle has a worm in it. “Some people think it’s just a gimmick,” says Kawahara.
To make matters even more confusing, there is also a species of butterfly called the tequila giant skipper. It probably earned this name because the species feeds on the agave plants that produce all forms of mezcal.
In the past, because of this connection, some people seem to have believed that the larvae in the mekal bottles came from the giant tequila skipper, “but that has nothing to do with that, it’s completely wrong,” confirms Kawahara.
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Digging Deep into the Tequila Worm Mezcal
The researchers sorted the initial worms they took home and even ordered a few more bottles available commercially in the US. But after deciding that such a difficult scientific question required more diligent research, they organized another trip to Oaxaca, the mezcal mecca in southern Mexico.
Kawahara and his colleagues visited various distilleries around the state in an effort to “understand the product,” he says. “It turned into a whole expedition.”
In total, they successfully sequenced 18 individual worms for a study published this year in PeerJ. DNA revealed that the species was indeed a moth: the agave worm moth (Comadia redtenbacheri) to be precise.
These moths, which are usually between 1.5 and 2 inches in size, lay their eggs on agave plants. After hatching, the larvae burrow into the heart of the plant, where they are relatively protected from predators.
They don’t come out again until they become moths or an agave harvester unceremoniously slices up their home for use in a mekal distillery. And while these worms often look pale in a bottle, they are much more colorful while alive.
“They’re very red, the caterpillars — they look like bright red rubber worms,” says Kawahara.
Mescal worms in danger
Based on what Kawahara can tell, the worms may still have ended up in mezcal as a kind of trick: someone must have moved one of the larvae from a plant to a barrel or bottle at some point. From there it just caught on.
However, this is unfortunate for the moths. Kawahara says there is some concern that their numbers are now declining due to overfishing. “The demand is getting higher and they don’t breed the caterpillars in captivity,” he says.
Instead, mezcal distilleries pay people for them, as a form of marketing for their bottles. They’re also ground up and used in a kind of salty seasoning that has a smoky flavor, Kawahara says.
It is possible for the worms to end up in the bottles themselves—just not in a visible way. Since the worms burrow into the plant itself, some of them may be crushed in the distillation process, perhaps even flavoring the mezcal.
In the course of their vigorous research, Kawahara’s team ate several of the worms and agreed they didn’t taste very good. Still, he says, there are plenty of other people who want the chance to do their own follow-up research.
“All my students want to go on this trip,” says Kawahara.
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