Clay Fragments Suggest How Long We’ve Been Relying On Honeybees

There’s a lot of worry right now about the future of bees, the friendly pollinators of a third of our food supply. Populations have been vanishing thanks to a condition called colony collapse disorder, and in the past few months, United States and English regulators have taken opposing decisions about allowing a pesticide that might be contributing to the problem.

But while the future might look murky, bees’ past is coming into clearer focus. Accidental discoveries made while investigating the diets of early farmers have allowed researchers to begin sketching out the long relationship between humankind and honeybees. And it may stretch back to 9,000 years ago.

Mélanie Roffet-Salque, an organic chemist and post-doctoral researcher in the Richard Evershed lab at the University of Bristol (which previously identified molecules from 7,000-year-old cheese), tells The Plate how the finds came about.

“What we have been doing over the last 20 years is examining food residues in archaeological pots,” says Roffet-Salque, who is the the first author of the paper about the research, published in the journal Nature on Wednesday. “Most of the time in potsherds what we find is animal fats, but from time to time, very rarely, we find beeswax. We tended not to report it in papers because we were usually writing up other things; so what we decided to do here is collate the data from the past 20 years to try to map the chronological and and spatial trends in hive product use in prehistory.”

Roffet-Salque and the lab she works in are part of the NeoMilk project, a multi-institution effort to map the spread of Neolithic cattle-raising. The pot fragments they have been analyzing come from excavations done in Europe, the Near East and North Africa.  Just 80 of the more than 6,400 sherds carried the molecular fingerprint of beeswax, allowing the researchers to begin to determine when and where people began to exploit bees for wax and presumably honey.

The finds will help light up the past history of bees—which don’t leave fossils, unless they have the misfortune to be trapped in amber. And they also contain surprises, including no evidence that bees were present in Ireland, Scotland or northern Scandinavia as agriculture moved into those areas, suggesting that bees subsequently had to be bred to tolerate those climates.

Roffet-Salque adds: “While we were writing, we realized there is no evidence for the presence of bees in the past 10,000 years in Europe. So this gave us an opportunity to talk about the ecological spread of honeybees at that time.”

Investigations of more recent history—such as classical Rome and Greece, about 2,500 years ago—have identified beeswax in lamps and jars, and traces of honey, which was used as a sweetener and a medication.

But the pots examined by the Bristol team date back about 9,000 years, to the point at which humans transitioned from living as hunter-gatherers to creating settlements in which they grew crops and domesticated animals. Based on their shapes, the pots were most likely cooking vessels; they were made between 7,500 and 2,000 BC, and come from a wide geographical range. One from Algeria represents the first evidence that early North African farmers were using bee products, and several from Anatolia and Central Europe push back the dates at which humans were thought to have access to bees.

(Roffet-Salque says the assumption is that Neolithic settlers both ate honey and used the beeswax as a natural waterproofing compound, but there is no molecular evidence for honey because its soluble sugars do not survive the millennia in the way that beeswax’s stable fats do.)

To identify the beeswax (and other food residues), the lab crushes a tiny sample of a pot into powder, mixes the powder with an organic solvent, and feeds it into a gas chromatograph, which Roffet-Salque describes as an “oven with a long, thin column inside.” The chromatograph separates out the components of the sample as they boil, and a mass spectrometer identifies them as mineral, vegetable, animal fats, or the unique chemical fingerprint of beeswax.

Because these results were the unexpected side products of 20 years of research, Roffet-Salque—who is primarily investigating when early farmers began milking in Central Europe—can’t say where the research will go next. “It would be interesting to investigate more in Spain and Portugal, because we haven’t had many pots from  there,” she says. “But it is very difficult to design a project around beeswax, because we see it on so few sherds.”