Sunday, June 8, 2003		Nature

TERMITES are perhaps the greatest engineers of animal world. There are 2000 plus known species of these tiny master-builders on earth, all have adopted different but species-specific architectural designs for their ‘cities’, each best suited to the environment in which they live. Found worldwide in warmer climates, termite-mounds are not just high-rising mud structures; they are full-fledged ‘cities’ with an intricate network of lanes, chambers, gardens, warehouses, nurseries and also factories.

Tiny in size, termites are in a habit of doing things on a grand scale. The mounds they build can reach astonishing heights of 28 to 30 feet above ground with a diameter of 100 feet and often extending below the ground to a depth of 8 to 9 feet. Inside these huge structures, which may contain about 12,000 tonne of fine sand particles, brought from underground, live millions of termites, divided in various castes (according to the work they perform) but living in perfect harmony as a single colony or a family unit. Each colony contains primary and secondary reproductives, workers and soldiers.

The world inside the termitarium or termite mound is completely different with several chambers, but the central royal chamber is situated at the heart of the nest where the queen, the single most important member around whom the whole termite society revolves, is attended to by her subjects or busy sterile workers of either or both sexes. Queen or her attendants never move out of the royal chamber instead they are fed and cleaned by workers there only, while her attendants’ job is to groom the ‘royal lady’ constantly.

If we look at the size, termites are few millimeters long, but the queen is entirely opposite with a length of 6 to 7 inches (15-18 cm), up to 1.5 inch across and weighing about 6000 times more than her subjects. Her huge abdomen is about 1500 times larger than the rest of her body. Queen’s only job is to keep on multiplying the population for which she lays about 35,000 eggs each day that are immediately removed by workers to ‘brood chambers’ for hatching.

Also known as white ants, these soft-bodied, winged or wingless, polymorphic (that have many forms) insects are neither truly white nor even true ants. Among the most destructive insects for the human race, termites feed on all vegetable matter, especially dry wood, which is digested with the help of symbiotic Protozoa in their gut. Related to cockroaches, termites belong to the order Isoptera with 2200 known and living species, most of which are restricted to the tropics.

Giant African fungus-growing termites build a high-rise termitarium from dried mud-pellets, which can be up to 26 feet high and about 10ft across. These ‘skyscrapers’ are well ventilated inside by a network of tunnels with fresh air being drawn in through nest walls and warm air rising from below escapes outside through tall ‘chimneys,’ minute holes in the hard surface.

These dwelling structures with curious exteriors are self-supporting units, with gardens of fungi, staple diet of termites, all cultivated by the insects themselves. Now the question is how this fungus is grown? It is grown on a bed of termite droppings, mixed with a small quantity of dead wood. Every nook and corner of the interior is planned. There is a specifically allocated place for everything, for instance food-storing place is higher up the mound, whereas royal chamber and the nurseries are below the gardens. There is also a separate place for the dead where all the dead bodies are dumped so that decaying corpses do not harm the health of the colony.

The deepest point inside the mound is a damp place that serves as a source for obtaining building material – fine sand particles – carried by workers from there to the highest point or wherever it is needed for construction. The amount of labour these insects undertake to build a mound can well be understood by the fact that in one case, a single nest excavated yielded enough material to manufacture about 451,000 bricks to construct a house.

Experts are of the opinion that the dampness comes from the condensation of water vapours from the breath of millions of these tiny insects. The water thus formed keeps on dripping constantly through the walls and floor maintaining the necessary dampness and the ideal temperature.

Compass termites of Australia have evolved an entirely different and unique way of keeping the interiors of mounds at proper temperature and right degree of humidity. These architects of the insect world always build their long, flat termitarium in a north-south plane. This gives a very natural kind of air-conditioning. During the cool of the morning and evening, the sunrays touch the broader side of the mound and heat it up moderately; but in noon when the sunrays are very intense and they fall on the narrow sides of the nest. Thus even the midday sun is not able to over heat the hill walls.