IT has always been assumed by scientists that early human species prospered on a diet of meat, nuts and leaves, but now ground-breaking research by Heriot-Watt University has shown that insects such as beetle grubs made up half of the diet of our distant ancestors.

Heriot-Watt academics teamed up with colleagues at Wayne State University in Detroit, Michigan, to discover that insects could have been a major source of food for hominids around 1.8 million years ago.

The discovery came about by chance, after tests were carried out on unusual-looking mud found during excavations at Olduvai Gorge, Tanzania.

When testing the mud at Heriot-Watt, it was confirmed the sediments were in fact an ancient termite nest.

And after comparing carbon signatures in fossil teeth found at the site to carbon signatures in the potential food source, academics made the ground-breaking discovery.

Dr Clayton Magill, Research Fellow at Heriot-Watt University, said: “The discovery came about by chance when I showed a friend who is an insect expert a picture of the unusual-looking soil and discovered it was in fact a termite nest.

“We have specialist equipment in the Lyell Centre which is only in a dozen or so labs worldwide, which was able to test, detect and isolate the fossils.

“We’ve found that insects were in fact a major food source millions of years ago, and now we want to go to other archaeological sites to see if any others exist.

“This is one of the most exciting and interesting research projects I’ve had the pleasure of working on and there is so much scope to find out more. We’ve been trying to make this connection for the past 40 years, and we’ve finally found it. It’s evidence of forensic evidence from the past, in action now.”

Dr Julie Lesnik, from the department of Anthropology at Wayne State University in Detroit, said: “Insects are an important food source for billions of people in the world today, but researchers tend to ignore this food source when reconstructing past diets.

“We now know that hominids at Olduvai would have been living alongside the exact type of termites that are preferred as food today and that they were likely too valuable of a food source to be passed up.

“Many people today are studying the potential of utilising insects in our modern diets as a way to feed the growing global population.”