DNA Testing Concludes That the Mezcal Worm Is Actually a Mezcal Moth — But Its Cultivation Remains Mystery

The subject of much debate among spirits enthusiasts, the mezcal worm has just been identified as a type of moth. Its origins, however, remain a mystery. (Photo by Sanka Vidanagama/NurPhoto via AP)

A new study published in PeerJ Life & Environment has identified the iconic but oft-reviled mezcal worm as a type of moth, though scientists are puzzled as to how it could be cultivated on a commercial scale.

For the study, scientists traveled to the epicenter of mezcal production in Oaxaca, Mexico, and collected 22 bottles containing the sunken larvae.

Since alcohol makes for an excellent preservative, the team was able to successfully DNA sequence 18 of their specimens, every one of which was identified as the agave redworm moth, Comadia redtenbacheri.

The initial discovery by itself wasn’t a revelation. The redworm moth, whose larvae infest the succulent leaves of naturally occurring agave americana and salmiana, had long been suspected as the wriggling culprit at the bottom of our bottles.

“It’s relatively easy to broadly determine the kind of larva based on the shape of the head, but their identity has never been confirmed,” said Akito Kawahara, curator at the Florida Museum’s McGuire Center for Lepidoptera and Biodiversity. “This is probably because most biologists are not looking inside mezcal bottles.”

The larvae of agave redworm moths are widely enjoyed as a delicacy throughout Mexico, used varyingly as a garnish, a main ingredient, and a form of salt (sal de gusano).  They’re also rumored to be an aphrodisiac.

Teodora Bautista Romero drops worms into bottles of Monte Alban mezcal at the Beneva mezcal bottling plant in Santiago Matatlan, Mexico.  (AP Photo/Arizona Republic, Chris Hawley)

Though these larvae may be a tried and true culinary staple, their presence within mezcal has long been called into question. It’s widely believed that the mezcal worm “tradition” began in the 1940s as a clever marketing ploy to distinguish low-grade brands on American liquor store shelves.

To the horror of many mezcal enthusiasts, these worms have established themselves as a mainstay in the industry. But scientists don’t understand how the practice has continued for all these years.

Warming temperatures and growing demand have led to a gradual decline in mezcal larvae. What’s more, harvesting these tiny critters in the wild is a time-consuming process, oftentimes requiring that their massive host plant be intricately dismembered.

It seems unlikely that mezcal brands are harvesting these worms naturally. Scientists speculated a handful of possible ways that these larvae could be raised in captivity, but concluded that all known methods would prove “challenging.”

“There is still very little known about how best to rear mezcal larvae and additional scientific research is needed to understand how captive insect breeding can become a central part of the agricultural industry in Mexico,” said the study.

There aren’t any transparency measures in place for their commercial cultivation. So, until spirits brands give up their secret formula, all we can do is speculate.

A new mystery has taken hold of the ever-unfolding mezcal worm folklore.

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