If biodiversity is one of the pillars of the sustainability of the African continent and the survival of its human inhabitants, then “Majeje” is a crucial brick without which the design would be very unstable.
Majeje or Makeke are the indigenous names for a group of edible termites known to science as Macrotermes – a genus grouping.
According to Stellenbosch University geneticist, Dr Barbara van Asch, Macrotermes termites are irreplaceable as service providers and their important role in African biodiversity has been underestimated.
“Macrotermes termites contribute to the long-term resilience of dry savannah ecosystems by enhancing soil properties and water availability. Additionally, Macrotermes termites are a source of nutrition and income for rural communities, and a fundamental part of ancestral cultures and food traditions in economically underdeveloped areas of South Africa,” she tells the FBIP.
African Macrotermes species are consumed by many communities as a traditional dietary complement and delicacy and are one of the most widely utilized edible insect species because of their relatively large size.
Of the 13 recognized species of Macrotermes occurring in sub-Saharan Africa, nine have been recorded as edible in Southern Africa. In South Africa, the harvest and trade of edible termites, mostly identified as Macrotermes falciger, Macrotermes natalensis and Macrotermes michaelseni, contributes significantly to the diets and livelihoods of many rural families in the Limpopo province.
The Macrotermes group of termite species has a wide distribution in tropical Africa and Southeast Asia. Most Macrotermes species build spectacular mounds that protect the colony from the harsh savannah environment because termites are very sensitive to dehydration and depend on the maintenance of a micro-climate with constant humidity and temperature.
The mound has been considered as the colony’s lung and hypothesized to function as a regulator of gas exchanges between the internal and external environments. This view has been challenged and it is possible that the mound is in fact a by-product of the water harvesting activity of the termites – termites may build mounds to dispose of the huge amounts of small particles of soil they bring from the lower layers as a vehicle for transporting water into the colony.
This task is performed by workers, who also constantly repair mound damage caused by wind, rain, animals and vegetation.
According to van Asch, the mound is just the tip of the iceberg of the Macrotermes colony because termites also move large amounts of soil while building interconnected underground galleries for food foraging that can extend as far as 70 meters from the nest.
“Macrotermes are known by ecologists as ecosystem engineers because they redistribute moisture vertically and horizontally, and also modify the properties of the soil by creating macropores that promote the infiltration of rainwater. The soil particles are enriched in micronutrients when they pass through the colony and the process contributes to the productivity of the land,” she explains.
In spite of the important role played by Macrotermes in African ecosystems and their nutritional and economic relevance, the diversity and geographic distribution of species on the continent is poorly known.
Van Asch says traditional taxonomy relies on the use of morphological characters to describe and discriminate between species, and termites have few of these that allow for unambiguous identification of similar species.
In their FBIP-funded study, published in the journal Insects, van Asch and her research team compiled new and publicly available DNA barcodes for African Macrotermes to obtain an overview of the genetic diversity of specimens found in a few countries, including South Africa.
The study concluded that DNA sequences are essential to catalogue the diversity of termite species because classic morphology-based methods fail to produce accurate and consistent results.
The study also provides the first overview of the genetic diversity of African Macrotermes. Van Asch says the findings can be divided into two main results: “first, we showed that the diversity of African Macrotermes is poorly described because vast areas of the continent have not been surveyed using DNA-based methods, which are essential to generate catalogues of biodiversity particularly in species that cannot be discriminated using morphological characters.
“Second, we showed that the diversity of Macrotermes species has been underestimated because there are 13 described species and we found 17 genetic groups that most likely represent distinct species. Additionally, our results evidenced the extent of the poor correlation between species as morphological groups and genetic groups, which is likely due to the lack of informative morphological characters for species identification in termites.”
Van Asch and her team believe that their study lays the essential groundwork for future DNA-based studies in African Macrotermes, and that it includes a workflow that can be used by other researchers to advance knowledge on the genetic diversity of termites.
As can be seen in the case of African Macrotermes, ecosystems are composed by complex networks of interactions between species and their physical environment. From an ecological perspective, every species plays a unique role in the balance and resilience of the environment.
It has become clear that human activities cause major environmental disruptions, and that biodiversity is being lost at alarming rates, and in many cases faster than species can be discovered and described.
Van Asch and her team hope that in the not-too-distant future there will be a shift in peoples’ perspective (particularly in communities where Macrotermes are found) on the utility of these and other seemingly irrelevant species. And that these termites are remarkable service providers and a source of human nutrition.
In her view van Asch says biodiversity is undoubtedly one of the pillars of the sustainability of our planet and the survival of human societies, and the notion that all species matter must be cultivated in the general public – South Africa is a biodiversity hotspot for many groups of animals and plants, and Macrotermes termites are no exception.
“We hope that our work contributes to promote Macrotermes termites as flagship species of the savannah, and that the average person may see termite mounds as incredible engineering structures built by agriculturalist species that play essential roles in the maintenance of healthy natural environments,” she says.