Termite " Mound "

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nds (also known as "termitaria"[6]) occur when an aboveground nest grows beyond its initially concealing surface. They are commonly called “ant hills” in Africa and Australia, despite the technical incorrectness of that name. In tropical savannas the mounds may be very large, with an extreme of 9 metres (30 ft) high in the case of large conical mounds constructed by some Macrotermes species in well-wooded areas in Africa.[7] Two to three metres, however, would be typical for the largest mounds in most savannas. The shape ranges from somewhat amorphous domes or cones usually covered in grass and/or woody shrubs, to sculptured hard earth mounds, or a mixture of the two. Despite the irregular mound shapes, the different species in an area can usually be identified by simply looking at the mounds. The sculptured mounds sometimes have elaborate and distinctive forms, such as those of the compass termite (Amitermes meridionalis & A. laurensis) which build tall wedge-shaped mounds with the long axis oriented approximately north–south which gives them their alternative name of compass termites. This orientation has been experimentally shown to assistthermoregulation. The thin end of the nest faces towards the sun at its peak intensity hence taking up the least possible heat, this allows these termites to stay above ground where other species are forced to move into deeper below ground areas. This allows the compass termites to live in poorly drained areas where other species would be caught between a choice of baking or drowning[8] The column of hot air rising in the aboveground mounds helps drive air circulation currents inside the subterranean network. The structure of these mounds can be quite complex. The temperature control is essential for those species that cultivate fungal gardens and even for those that don't, much effort and energy is spent maintaining the brood within a narrow temperature range, often only plus or minus 1 degree Celsius over a day. In some parts of the African savanna, a high density of aboveground mounds dominates the landscape. For instance, in some parts of the Busanga Plainarea of Zambia, small mounds of about 1 m diameter with a density of about 100 per hectare can be seen on grassland between larger tree- and bush-covered mounds about 25 m in diameter with a density around 1 per hectare, and both show up well on high-resolution satellite images taken in the wet season.[9]