For roughly 80 years, a pale, shriveled worm has floated at the bottom of mezcal bottles, but nobody knew exactly what it was. Scientists, drinkers, and distillers had offered different answers over the decades, naming three different insects as possibilities.
A team led by Akito Kawahara from the Florida Museum decided to find out the truth. They bought 21 bottles of commercial mezcal and traveled to Oaxaca to source bottles directly from distilleries. Then they removed the worms and analyzed their DNA.
The results, published in the journal PeerJ, were clear: every specimen belonged to one species, Comadia redtenbacheri, the agave redworm moth. The researchers successfully sequenced DNA from 18 larvae using the standard method for identifying animal species.
The study also solved another puzzle. Some bottles contain a ghostly white worm instead of the usual reddish one. This pale variant is not a different creature but the same redworm, gradually losing its color after years in alcohol.
In Mexico, these larvae are called chinicuil or gusano rojo and are eaten as a regional delicacy. The custom of putting them in bottles started around the 1940s as a marketing idea, not an ancient tradition.
However, the discovery comes with a serious problem. As mezcal sales grow, more worms are needed. Harvesters must split open agave plants to collect the larvae, which often kills the plants. Recent research shows this harvesting could reduce wild agave populations by up to 57 percent. Wild populations of the redworm moth are now at risk of overharvesting.