Thousands of years before cultural taboos emerged in the West, Europeans were already genetically predisposed to turn their noses up at insects. A sweeping genomic analysis of 33,000-year-old dental calculus reveals that the aversion to eating insects in Northern Europe isn't simply a modern cultural quirk—it has deep biological roots stretching back millennia.
The discovery, published in Science Advances by researchers at the Institute of Evolutionary Biology (IBE), a joint center of the Spanish National Research Council (CSIC) and Pompeu Fabra University (UPF), reframes a global food challenge. As climate pressures and population growth create urgency around alternative protein sources, the Food and Agriculture Organization of the United Nations has identified 1,611 edible insect species as sustainable solutions. Yet Western societies remain stubbornly resistant to entomophagy—the consumption of insects—despite hundreds of millions of people worldwide already incorporating them into their diets.
To understand why, the IBE team analyzed 745 samples of dental tartar from anatomically modern humans spanning up to 33,000 years. Tartar preserves DNA traces from regularly consumed foods, offering a biological record of what ancient diets actually contained. The findings were striking: DNA evidence showed that modern humans in northern Eurasia engaged in insect consumption only sporadically and accidentally, not as a dietary staple. This pattern contrasts sharply with tropical regions, where insect consumption appears to have been more frequent and deliberate.
The genetic story became even more revealing when researchers examined human genes involved in digesting chitin, the tough compound that forms insect exoskeletons. North Eurasian populations carry chitinase gene mutations that significantly reduce their capacity to digest insects—a trait that has persisted unchanged for at least 9,000 years, since the rise of agriculture. "The scarce presence of insects in the diet of northern Eurasians suggests that the absence of entomophagy is not solely due to recent cultural factors, but also to a long ecological and evolutionary history," explains Pablo Librado, principal investigator who led the study.
The research also illuminates a striking difference between modern humans and our evolutionary cousins. Neanderthals, despite sharing the same environments, showed far greater abundance of insect DNA in their dental calculus—levels comparable to those found in western chimpanzees that rely on insects to supplement their savanna diets. Neanderthal tartar contained particularly high concentrations of Diptera (flies and mosquitoes), suggesting these insects were consumed regularly, possibly from animal carcasses infested with fly larvae or stored near water where mosquitoes bred. Neanderthals possessed chitinase genes that actually facilitated insect digestion—a capacity modern northern Europeans lost.
Meanwhile, tropical and subtropical populations maintained genetic variants associated with higher expression of insect-digesting enzymes, a pattern sustained across both ancient and modern samples. Manuel Piñero, first author of the study, notes that tropical regions offer a clear advantage: "Large quantities of insects need to be ingested to compensate for the high caloric expenditure involved in their collection. In the tropics, there is a greater availability of social insects, such as termites and locusts: their biomass and diversity allow for sustainable exploitation throughout the year, which even contributes to pest control."
As Western nations grapple with feeding a growing population under ecological constraints, this ancient genetic legacy presents both a puzzle and a possibility. The research suggests that overcoming the Western aversion to insects may require more than cultural reframing—it may demand scientific solutions that account for deep evolutionary disadvantages that shaped our ancestors' digestive systems tens of thousands of years ago.