Gold is a valuable precious metal. It has been used throughout history as money and for jewelery production. Today it has many more applications, including uses in medicine, electronics, and even food and drink. Gold is therefore highly sought after, and a demand for it is always present. Although many mines exist for the extraction of gold from the ground, as these run dry we need to find new areas which can supply gold. Exploration for these sites is a very costly activity and proves difficult at times. Intriguingly, ants and termites may be the answer to this problem.
An earlier study found that mounds produced by the termite T. tumuli can successfully be used to detect gold concealed below because this mineral was also present in the nest itself. Not all termites build mounds on the surface of the earth, however; some form large nests underground. These termites are particularly abundant in areas of Australia where gold can be found. This led researchers to start investigating whether these subterranean mounds could also be used to indicate the presence of gold. In a study published in the Journal of Geochemical Exploration, two researchers collected soil samples from 3 different types of nest; mound-forming termites, subterranean termites, and an ant species. They did this along a transect in an area known to contain particular minerals, such as gold, allowing the scientists to see how or whether the content of the nests represents what lies beneath. They also used sampling points where the mineral content of the ground was unknown for comparative measures.
The study found that ants brought the largest concentration of gold to their nests; up to 24.4 parts per billion of gold was found in the nest material, in comparison to 7.4 and 8.4 of the mound forming termite and subterranean termite, respectively. They also found that the insects could vertically move the indicators gold, copper and zinc from at least 1.4m deep.
This was the first study to investigate the usefulness of subterranean nests in geochemical exploration. It demonstrates that the insects investigated could be an extremely useful tool in the identification of areas containing valuable minerals, with the potential to reduce exploration costs and time.