A reluctance to eat insects in Western cultures may have roots that stretch back thousands of years, far longer than any living cultural tradition.
Researchers from the Institute of Evolutionary Biology, a joint center of the Spanish National Research Council and Pompeu Fabra University, used genomic evidence to trace patterns of insect consumption across human prehistory. Their findings, published in Science Advances, show that modern humans in northern Eurasia stopped eating insects regularly around 9,000 years ago, roughly the same time that agriculture began to spread across the region.
According to Science Daily, the team examined 745 samples of dental calculus, the hardened tartar that builds up on teeth over a lifetime, from anatomically modern humans whose remains dated back as far as 33,000 years. Dental tartar can trap and preserve DNA from consumed species, giving researchers a window into what ancient people actually ate.
The results showed almost no trace of insect DNA in the dental samples from northern Eurasians. That absence matched genetic evidence from living populations. Among North Eurasian groups, genes involved in breaking down chitin, the tough material that makes up insect exoskeletons, carry mutations that reduce that digestive ability. Those mutations have been present for approximately 9,000 years.
By contrast, populations living closer to the tropics retained more functional versions of those chitinase genes, suggesting that insect consumption remained a regular part of their diets well into the historical period and possibly to the present day. Neanderthals also appear to have consumed insects more regularly than modern humans living in northern Eurasia.
"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," said Pablo Librado, the study's principal investigator.
The findings carry practical weight. A total of 1,611 insect species are currently classified as edible, and organizations including the Food and Agriculture Organization of the United Nations have promoted insects as a potentially sustainable food source as the global population grows and climate pressures mount on existing food systems. But widespread resistance to eating insects in Western countries has complicated those efforts.
The new research suggests that resistance is not simply a matter of habit or squeamishness learned in childhood. For northern Eurasian populations, the shift away from insect consumption appears to be both ancient and biological. Whether that genetic legacy can be overcome through food culture changes or dietary technology remains an open question the study does not address.
