Natural Architecture: Termite's mound

About three days ago, I saw a huge mound built by termites, and just yesterday, I saw a swarm of winged reproductive termites all around lightbulbs in the neighbourhood. Both sights gave me a nostalgic feeling of how we used to hunt for the winged reproductive termites in my younger days. Locally known as 'esunsun' among many Yoruba-speaking Nigerians, the winged reproductive termites represent a stage in the life cycle of termites generally.

The mound of termites is a structure that can be as high as 17 feet or even more depending on the species of termite. It is built using only soil and water, often supported by the saliva of tiny insects. Despite the simplicity of the materials used in their construction, termite mounds are usually very strong and have been analyzed to have a safety factor that ranges between 50 and 100 depending on the shape. To better understand how strong the termite's mounds are, anthropological buildings have safety factors that range between 1 and 3.

A typical mound of termites consists of 4 above-the-ground structural components, namely:

1. The column whose interior forms a part of the ventilation and cooling system of the entire structure
2. The base which contains openings for entry and exit
3. The outwash consist of an eroded part of the structure.

According to research, it takes an average of 3 to 4 years for a mound to be fully built. One major hindrance to the building of mounds by termites is rain as water has the capacity to destroy what is freshly built. After drying completely, rain no longer poses a problem.

Back then, apart from hunting for winged reproductive for food (yes, we fry them or even eat them raw), we also hunt for queens of castes. Termites are one of the few social insects that practice a caste system. The winged reproductives are just one of the castes of termites whose primary function is to reproduce. This happens during swarming or what is otherwise known as the 'nuptial flight'. The male reproductive becomes the king while the female reproductive becomes the queen of a new colony. The queen is characterized by an enlarged abdomen as a result of housing eggs. When conditions are favourable, the queen produces winged reproductives which live the colony to go and start a new life.

Getting the queen means that we have to dig through the mounds of termites and engage in fierce battles with the soldiers of the colony. Looking back now, I find the adventure totally not worth it because the effort we will have to invest in order to get the queen is significantly more than the satisfaction derived from eating it. It was during these periods of hunting for termite queens I got to know that there are different chambers serving different functions within the mound (even though I did not understand it back then). The inner chambers include:

1. The royal chamber where the king and the queen reside
2. The storage chamber where foods are stored
3. The fungal garden
4. The cellar
5. The nest chamber

The fungal garden is perhaps the most interesting chamber in the architecture of the termite's mound. Fungi are cultivated and eaten in order to maintain the intestinal microbiota which enables them to digest cellulose in woods and plant materials. The architectural structure of the mounds ensures that the ambient temperature is at the optimum level for the cultivation of the fungi.

As sturdy as mounts of termites appear, it is interesting to know that they are usually porous/permeable to air. Termites need to exchange gas in order to stay alive and living some feet below the ground with an impermeable superstructure is a recipe for self-destruction. Thus, the interiors of the termite mounds are designed in such a way that gaseous exchange is made easy and has been likened to the lungs in humans.

Final Words

There are several amazing human architectures, no doubt. However, the natural architecture in the form of termite mounds continues to be one of the most amazing edifices that are not built by man. Termite mounds are usually in a constant state of repair and modifications according to the needs of the colony. Thus, it is rare to find defected mounds unless accidents happen to them either naturally or anthropogenically. Even at then, the repair is usually swift as the workers are always ready to work.

Thank you all for reading.

Resources

• https://india.mongabay.com/2020/10/architectural-secrets-of-termite-mounds/
• https://www.orkin.com/pests/termites/colony/reproductive-termites
• https://www.nationalgeographic.com/animals/article/140731-termites-mounds-insects-entomology-science
• https://www.pbs.org/wnet/nature/the-animal-house-the-incredible-termite-mound/7222/
• https://www.frontiersin.org/articles/10.3389/fphys.2014.00127/full