The air is 40 degr C (104 degr F) and filled with insects that want to crawl into your nose and ears to establish a new colonies. The earth is infested with wood munching termites that will eat your house from under your feet and the chop sticks out of your hands before you can finish your sushi. Every liter of open water is packed with crocodiles that can’t wait for you to come in for a swim. After 20 years of protection, they inhabit swimming pools, ponds, rivers, lakes, creeks and the ocean. Oh yes, and did I mention limb-robbing shark attacks and jellyfish stings that require opium to manage the pain and can be fatal?
Welcome to Australia! Few places in the world have lower population densities than Australia; among those are the Sahara, Mongolia and Greenland. No wonder! Who wants to live in these places? At least in Greenland you can swim in the ocean and might get cold but you don’t have to fear for your life, and the worst that can happen to you in Mongolia is that somebody serves you goat brains for dinner in a yurt. Once you have visited Australia, you sure understand why it takes a special people to survive in this environment!
Our entry point to this vast and intriguing continent is Darwin, a port city of 129,000 people in the Northern Territories or the “Top End” as the Aussies call it. We are here to count termites. This should be relatively easy since termites can only be found between 50 degr north and south. To find the really big termite mounds we have to go to Litchfield National Park, a 2 hour drive south of Darwin. As we leave town, we head along the Stuart Hwy, the road that leads to the very bottom of Australia. On both sides of the highway we see fields with horses, emus and hundreds of termite mounds.
There are four types of termites living at the Top End of Australia. Because of their thin skin and lack of colour, the termites are often referred to as white ants. This classification is incorrect, however, as ants are predators whereas termites feed on wood. Actually, termites are a type of cockroach.
The first type is the Tree-Piping Termite (Coptotermes acinaciformis) that loves to eat live trees. If I were a tree and saw a bunch of termites congregate at the base of my trunk, I would start worrying. The earthen mounds at the base of tree trunks are their nests from which the termites attack the tree, hollow it out and weaken the tree structurally while making it more prone to damage from fire and wind. It is estimated that more than 50 % of all eucalypt trees in the Top End of the Northern Territory have been piped by Coptotermes. In some woodlands in the Northern Territories, 70 % of the trees are hollowed out. The advantage is that the piped branches can serve as nesting sites for small birds and the aboriginals can use them for dijeridoos.
The second type is the Cathedral Termite (Nasutitermes triodiae) which is known for building enormous columnar structures which sometimes can exceed 6 m (19 ft). Just think, the construction of a large cathedral mound is equivalent to 1 million blind-folded people joining forces to build a skyscraper covering 8 city blocks and towering over 1 mile into the sky. This termite type prefers well-draining sites and lives under ground as well as above ground.
The Magnetic Termite (Amitermes meridionalis) is the third type. These termites are famous for their remarkable mound structures which are flat and tomb-stone like. Taking advantage of their ability to sense the earth’s magnetic field, the termites minimize solar capture and overheating of their mounds by orienting their homes in a north-south direction. Thermal control is especially important to this type of termite as they live on grassy wetlands and can only live above ground. Scientific measurements have shown that the humidity inside the mound columns is maintained at 95 to 99%, while the temperature only varies by +/- 1 degr C during the day. That is a good thing if you are a termite worker maintaining a brood.
The fourth type is the Giant Northern Termite (Mastotermes darwiniensis). These lovely creatures are the most destructive and cause billions in damage to homes, gardens, crops and orchards all over the country. They have a ferocious appetite and attack almost everything under the sun, including wood, plastic, electric cables, leather, wool and rubber. In Australia, a huge pest control industry benefits from the destructive habits of this type of termite.
All of the above types benefit from working together as close-knit colonies. A caste system clearly defines everybody’s role. There is the queen which is enormous in size and can produce between 20,000 – 30,000 eggs per day! She can reach 45 years of age and will mate with one king all her life!! Because of her enormous size she cannot move very well and has to be fed by the workers. Then there are the “alate” which are the only winged termites. They are responsible for establishing new colonies and will leave the mound after the first rain in the rainy season. The alate are the only termites with vision. The next caste is that of the workers. They do the foraging, are responsible for food storage, they look after the brood and the nest maintenance and are the most likely termites to be found in infested wood. Finally, the soldiers are responsible for the protection of the nest or mound. The soldiers have an enlarged jaw and cannot, like the queen, feed themselves. They block the tunnels and can rebuff attacks from the “Green Tree Ants” which are the arch enemies of the termites.
The impressive looking nests and mounds in my pictures are constructed by termite workers using a combination of soil, mud, chewed wood, saliva and feces. Often, the mounds only represent the above ground structures and hide the tunnels and subterranean chambers underneath. The existence of underground nests makes eradication difficult as the termites can continue to live and prosper after the above ground structures have been destroyed.
Given that termites are quite vulnerable outside their mounds and require moisture and protection at all times, they have the tendency to build shelter tubes to cover their trails. Often, these run up and down trees for several meters. Trouble is, the more protection you build up around you, the more likely it is that the tubes and tunnels are breached. When that happens, the first responders alert the other soldiers and workers by banging their heads against the wall. The soldiers will then, very much in suicidal and sacrificial fashion, patch the breached tunnel from the outside before they are eaten by ants.
If you ever tried to eat wood you’ll know that it is difficult to digest. Lucky for termites, evolution has given them ways to digest cellulose using microbes in their guts while producing hydrogen and methane in the process. Termites can produce 2 liters of hydrogen from the digestion of a single sheet of paper! Essentially, they are 3 mm long bioreactors on 6 legs! Someone really smart has calculated that the world’s termites are responsible for 11% of all methane emissions on earth. As you may know, methane is one of the most harmful greenhouse gases. So far, attempts to harness the termites’ hydrogen and methane producing capabilities to generate energy, have failed.
But, not all is bad. Termites are wonderful soil conditioners. All those underground tunnels enhance water infiltration, reduce water runoff during heavy rains and, consequently, reduce soil erosion. Termites also create habitats for other creatures, assist in soil formation and, particularly the winged alates, serve as a food source for countless predators when they do their once a year flying exercise. The cleverly constructed mounds of the magnetic termites have also inspired human architects to use the same passive cooling principles when planning shopping centers and office buildings in hot climates. And finally, it has been known for centuries that termite mounds are clear indicators for the location of underground water arteries. This fact has been exploited especially in ancient India. Oh, I almost forgot: termites are also delicious pan-fried and served as a food source in many countries. They are supposed to have a particular nutty flavour. In some cultures, the queens are considered a delicacy. Australian aborigines don’t like to eat termites. Perhaps that is the reason why there are so many termite colonies left.
As we drive through the woodlands of the Northern Territories, I notice thousands of dead trees and hectares of burnt forest, so you can imagine my surprise when I climb up the side of Wangi Falls in Litchfield National Park and see nothing but green as far as the eye can reach. Somehow over the millennia, the termites and the forest have found a balance. It is as if the termites and the trees have reached an agreement: for every tree we kill, we’ll leave one alone. I should also mention that some trees have found ways to defend themselves by secreting anti-feeding chemicals such as oils, resins and lignin. Now, that’s ecology in balance!
As for my termite counting, I counted 359,872,455,122,904.735,849,188,976,004,197,444,159 termites in the Top End. My qualified assessment of the termites' conservation status: no risk of extinction any time soon.