Termite mounds
A termite mound is the aboveground part of a termite den. In addition, certain species of termites also build earth nests (underground) and cardboard nests (on trees).
structure
Different species of termites build very different termite mounds. The most important thing is the function.
Termite mounds can become very large and harbor several million termites. In Africa and Australia in particular , they often shape the image of savannah landscapes. In structures of the African termite species Macrotermes bellicosus (syn. Bellicositermes natalensis ) heights of up to seven meters and a base diameter of up to 28 meters were measured. The largest structures are built by an Australian species from the Nasutitermitinae subfamily . The building material of the termite mounds is made up of earth and chewed plant material ( cellulose ). This mixture can achieve enormous strength and hardness. In combination with possible repopulation of the mounds by the same or different species, termite mounds in some areas can live for several thousand years.
The center of a termite mound in most Macrotermitninae is the chamber with the termite queen, usually the only fertile female that produces all the eggs of the insect colony. The mostly concentric structure extends around the queen's chamber. It can be very complex and divided into several galleries. The chambers for eggs and smaller larvae are located near the queen chamber. The chambers for larger larvae and worker termites follow on the outside. This is followed by the mushroom chambers, in which the workers cultivate edible mushrooms as the main source of food for the termite population. The entire building is criss-crossed by a complicated labyrinth of corridors and air shafts.
Functions
While some species store dry plant material for later consumption, species of the subfamily Macrotermitinae cultivate fungi of the genus Termitomyces in an obligatory symbiosis , whose asexual fruiting bodies represent an important food source for the colony. The fungus is cultivated on pre-digested plant material from which the termites have extracted more easily digestible parts. Termitomyces continues to degrade this material. Colonies of species that cultivate fungi require a particularly stable homeostasis with very low fluctuations in temperature and humidity. Different hill architectures have evolved within different types of macrotermitine to ensure this. To a limited extent, the species also react to environmental changes and adapt their architecture.
Mainly these termite mounds serve to protect against the weather and to regulate the climate. The complex structure of corridors, air shafts and insulating layers of insulation ensures that the building has a uniform, relatively cool climate, even in the hot zones of Africa and Australia . Some termite mounds have towering battlements for air conditioning with wind shafts through which fresh, cool air is constantly forced into the innermost areas of the building. The mounds of the Australian compass termites are elongated and, due to their magnetic sense, laid out in a north-south direction, so that only the narrower side faces the sun and the burrow does not heat up as much.
The hill also serves to protect against predators, which is why it is often referred to as a "fortress". Few animals that specialize in hunting for termites are able to break through the rock-hard walls of a termite mound. This includes anteaters in particular , but also aardvarks and armadillos , which can dig holes in a termite mound with their strong claws. If its burrow is broken open, the termites immediately start to close it again. The most important predators of termites are ants, which penetrate termite nests above or below ground and can prey entire colonies in a very short time.
Abandoned termite mounds
Termite mounds that are no longer inhabited represent special micro-habitats due to the changed soil conditions, which differ from their surroundings. In West Africa, for example, certain trees and shrubs such as the tamarind or African ebony , but also many succulent plants are preferred or exclusively found on termite mounds. Even after thousands of years, such differences can still be clearly seen, as the so-called Heuweltjies in South Africa and Namibia show.
Termite mounds in the Caatinga
In the semi-arid Caatinga , a landscape in northeastern Brazil, structures of the Syntermes dirus species that are several thousand years old have been found. The total of around 200 million spoil heaps of the presumably mushroom-growing gardeners only became more clearly visible for grazing when the vegetation was cleared; Research results of the entomologist at the University of Salford , the expert on bees Stephen J. Martin, in collaboration with the University of Feira de Santana in 2018 showed a total volume of 10 cubic kilometers of the earth moved for the underground structures, which is in comparison 4000 times the pyramid of Cheops built by humans . The up to 3800 year old hills, which are regularly distributed over an area of estimated 230,000 square kilometers in the bush, are not nests or typical termite mounds; the overburden from the branched, extensive tunnel system between the entrances was transported to the surface of the earth. The distribution of the mounds of earth (also known as murundus ) was compared by the researchers with the spatial patterns of the fairy circles in southern Africa, the mima mounds in North America and also with the underground networks of the naked mole rat ( Heterocephalus glaber ). In their way of life, the architects of the buildings are closely connected to the ecosystem and the periodic leaf fall caused by the drought in the Caatinga, the termites are dependent on the biomass of the leaves around the entrances under the approximately 2 meter high termite mounds and will leave their buildings removed the trees and bushes.
mythology
Termite mounds in Africa are presented in some traditional beliefs as the seat of earth gods or earth spirits. There are African myths in which the first humans came out through an opening in termite mounds. In other mythical tales, a hunter penetrates the underworld while chasing a game through a termite mound and only finds his way out after a dangerous action.
According to an Indian myth, the kingdom of the snakes ( Nagas ) lies underground , to which only one entrance leads through the termite mound. The worship of termite mounds has a tradition in India that goes back to Vedic times and is still practiced today in popular religious cults in many parts of the country. In a Vedic ritual text that was written before the middle of the 1st millennium BC Ants (equated with termites) use mud to build the first mound on the primordial ocean. Later the mound of earth enlarges into the central world mountain of the cosmogonic order. Such a sacred anthill is associated with a mostly female village deity. The believers walk around it ritually in a clockwise direction and make vegetarian offerings.
literature
- JPEC Darlington: A method for sampling the populations of large termite nests . In: Ann. Appl. Biol . No. 104 , 1984, pp. 427-436 .
- Judith Korb: Thermoregulation and ventilation of termite mounds . In: Natural Sciences . No. 90 , 2003, p. 212-219 .
- Judith Korb: Termite mound architecture, from function to construction . In: DE Bignell, Y. Roisin, NT Lo (Eds.): Biology of Termites: a modern synthesis . Springer, 2011, ISBN 978-90-481-3976-7 , pp. 349-374 .
- MG Lepage, JPEC Darlington: Population Dynamics of Termites . In: T. Abe, DE Bignell, M. Higashi (Eds.): Termites: Evolution, Sociality, Symbioses, Ecology . Kluwer Academic publishers, 2000, ISBN 0-7923-6361-2 , p. 333-362 .
- JM Moore, MD Picker: Heuweltjies (Earth Mounds) in the Clanwilliam District, Cape-Province, South-Africa - 4000-Year-Old Termite Nests . In: Oecologia . No. 86 , 1991, pp. 424-432 .
- Hans Schmidt: Termites (The New Brehm Library) . 3. Edition. Westarp Sciences, 2003, ISBN 3-89432-509-7 .
Web links
Individual evidence
- ↑ sueddeutsche.de : Oldest termite construction in the world - construction time: two millennia
- ↑ a b Kenneth Chang: A Metropolis of 200 Million Termite Mounds Was Hidden in Plain Sight , The New York Times , November 20, 2018.
- ↑ Where termites have been building a huge city for 4000 years , Süddeutsche Zeitung , November 23, 2018.
- ↑ Termite mound area discovered: As big as the British island - "It's unbelievable" , Die Welt , November 22, 2018.
- ↑ Stephen J. Martin, Roy R. Funch, Paul R. Hanson, Eun-Hye Yoo: A vast 4,000-year-old spatial pattern of termite mounds. In: Current Biology . 28, 2018, pp. R1292 – R1293, doi: 10.1016 / j.cub.2018.09.061 .
- ↑ Hermann Baumann : Creation and primeval times of man in the myth of the African peoples. Dietrich Reimer, Berlin 1936, p. 93.
- ^ John C. Irwin, The Sacred Anthill and the Cult of the Primordial Mound. In: History of Religions. Volume 21, No. 4, May 1982, pp. 339-360.