DNA Analysis Identifies Mysterious Mezcal Bottle Worm as Single Species of Agave Redworm Moth

Florida Museum scientists use DNA to prove the mezcal "worm" is an agave redworm moth caterpillar, raising new concerns about the sustainability of wild harvesting.

By: AXL Media

Published: Apr 27, 2026, 7:26 AM EDT

Source: Information for this report was sourced from ScienceDaily

Decoding the Identity of a Global Curiosity

The curled "worm" found at the bottom of certain mezcal bottles has served as a cultural icon and marketing curiosity for decades. Despite its fame, the biological identity of this stowaway remained a subject of speculation, with various theories suggesting it could be a butterfly, moth, or even a weevil. Now, a collaborative study led by Akito Kawahara at the Florida Museum of Natural History has utilized DNA sequencing to provide a definitive answer. The research reveals that these larvae are not a mixture of various agave-dwelling insects but are consistently the caterpillars of a single species.

Genetic Evidence Points to the Agave Redworm Moth

To conduct the study, the research team traveled to Oaxaca, Mexico, to sample larvae from a wide variety of commercial mezcal brands. Genetic material was extracted from 18 specimens, and the results were uniform: every usable DNA sample matched Comadia redtenbacheri, commonly known as the agave redworm moth. This contradicts previous theories that the larger, white larvae of the tequila giant skipper butterfly were the primary source. Researchers noted that while the "worms" often appear pale or white in the bottle, this is likely due to the alcohol leaching the caterpillar’s natural reddish pigment over time.

A Tradition Rooted in the Mid-Twentieth Century

While mezcal production has a history spanning centuries, the practice of adding larvae to the bottles is a relatively modern invention. Evidence suggests the trend began in the 1940s, likely as a marketing strategy to differentiate certain brands or impart a specific flavor profile. In Mexico, these larvae—known as chinicuiles—have been a staple of traditional cuisine long before they were preserved in spirits. However, the commercial success of mezcal on the international stage has transformed these insects from a local delicacy into a globally traded commodity.