African Termites

To discuss our Namibian Termites and African Termites in general, one first needs to understand that Termites can be roughly grouped into those species that nest within their food (those nasty ones who help you destroy and break-down any wooden structure), usually wood, and those that nest elsewhere and must leave their nest in order to forage for food. Of the latter type, nests may be arboreal or subterranean, centrally located or dispersed into small, connected units. Most termites shun the open air and travel to and from the foraging area by way of subterranean tunnels or covered galleries. Many species also cover the foraged material with sheet galleries before dining (Intro photo: Hypopharynx Pseudergates by Webstagram)

In the central Namib desert, the subterranean termite Psammotermes allocerus Silvestri (Isoptera: Rhinotermitidae) builds its nest structures nearly 30 em deep into the dry sand of the Kuiseb river. Gallery systems protect the insects against unfavourable climatic conditions and reduce body-water loss occurring in all humidities below 98% Rh. Furthermore, the social structure of a termite colony contributes essentially to a reduction of individual water loss in subsaturated atmospheres as well as to a more efficient water uptake. Water vapour uptake from the atmosphere is not possible and free liquid water cannot be used as a water resource because of the strong surface tension of the water droplets. However, with the aid of their hypopharynx pseudergates of Psammotermes allocerus are able to extract water from the capillary system of loamy sand. The role of “water-sacs” in connection with water uptake and storage is still unknown.

 

 

 

 

 

The Photo above: Psammotermes allocerus (by unknown)

Many termites do not build mounds that show above ground, but construct entirely subterranean nests, with tunnels to the surface. The best known of these is the African harvester termite, Hodotermes mossambicus, largely thanks to occasional subterranean encounters during the digging of trenches for construction (Coaton and Sheasby 1975; Hartwig 1963, 1965). Large passages connect these subterranean nest to each other, and smaller ones give the termites access to the surface where they dump excavated soil and forage for grass. Foraged grass is first placed into small, superficial chambers for later transport to the nests and consumption. None of the reports on subterranean gallery systems describes architectural details of the tunnels themselves, or how they are constructed.

Termite mounds comprise a significant part of the landscape in northwestern Namibia. The vegetation type in this area is mopane vegetation, a vegetation type unique to southern Africa. As a first timer visiting Namibia one should notice the fact that, almost all termite mounds coexisted with trees, of which 80% are Mopane trees (Colophospermum mopane). Also, according to multiple biological studies, it was determined that the rate at which trees withered was higher on the termite mounds than outside them, and few saplings, seedlings, or grasses grew on the mounds, indicating that termite mounds could cause trees to wither and suppress the growth of plants. However, even though termite mounds appeared to have a negative impact on vegetation, they could actually have positive effects on the growth of mopane vegetation. Moreover, local people use the soil of termite mounds as construction material, and this utilization may have an effect on vegetation change if they are removing the mounds that are inhospitable for the growth of plants. Consequently, both termite mounds and human activities should be taken into account as factors affecting mopane vegetation as a whole.

 

 

 

 

 

 

The Photo above: Mopane Tree (by Etosha National Park)

As we mentioned above, the savannas of Namibia are dotted with the spectacular mounds of the fungus-growing termites of the genus Macrotermes (Termitidae: Macrotermitinae). These mounds can reach several meters high and represent a colossal engineering project for the termites that build them. These little insects are working and building like there is no tomorrow. According to modern research, the mound is a respiratory device, built to capture wind energy to ventilate the subterranean nest. The need for ventilation is of the highest importance. A typical Macrotermes nest contains roughly a million workers and a substantially larger biomass of the fungi they cultivate. Collectively, these organisms consume oxygen at rates similar to that of large mammals.

 

 

 

 

 

 

By various estimates, a single Macrotermes colony is the metabolic equivalent of a goat or a cow. Macrotermes mounds are also external organs of homeostasis. The composition of the nest atmosphere is tightly regulated. Typically, oxygen concentrations in the nest are 2% lower than the surrounding air, carbon dioxide concentrations are commensurably higher, and nest humidities are very high. These conditions are maintained throughout the year and in the face of considerable variation of metabolic demand from the colony. Such stability can only come about if the termites can match ventilation rate with the colony’s respiration rate.

 

 

 

 

 

 

They do this by making the mound a “smart” structure, which means that it must also be a dynamic structure. The soil is continually eroded from the mound and is replaced by soil carried by termites out to the mound surface. Roughly a cubic meter of soil moves through the mound each year in this way. The mound’s architecture is therefore shaped by the relative rates and patterns of erosion from, and deposition to, the mound. For the mound to be an organ of homeostasis, these patterns of active soil movement must be coupled to the composition of the nest’s atmosphere. For example, excessive ventilation rates would produce patterns of soil transport that reduce the mound’s capture of wind energy. Insufficient ventilation would elicit soil transport patterns that enhance the capture of wind energy.

 

 

 

 

 

 

Photos above: Southern Africa Termite mounds (by unknown)

     + Termites Harvesting for Food
In African tropical countries, most insects are collected from the wild. Such is the case for termites. The tribes of Africa, especially those in Zambia, the Central African Republic, Angola, and the DR of Congo, collect winged sexual forms at the time of nuptial ights of species, such as Macrotermes falciger and Macrotermes subhyalinus, when adults emerge in large numbers from the termitaries subsequent to the maiden rains (Malaisse 2005). Harvesting is mostly seasonal; for instance, in Ghana, Macrotermes bellicosus is available for harvesting only in June and July. In East Cameroon, termites are only harvested in the rainy months of March, April, and May. Termites were collected in Kenya during the short rain season from March to May and the long rainy season from September to December.

 

 

 

 

The photo above: Dried Termites (from Springer link)

The termites are attracted by light from a lantern lamp causing them to fall in large swarms and are collected and put in a clean container. Van Huis (2003) reviewed various methods of termite collection around Africa. The most popular and easy way used in the tropics is to collect them during the evening hours, by placing a basin of water right under the light source. As light is reflected on the water, termites are attracted and trapped on the water surface.

In the DR of Congo, a basket is put upside down over an emergence hole of the mound. In the alternative, a dome-shaped framework of sticks is built up, or elephant grass is covered with banana leaves or a blanket, to cover part of the emergence hole near which a receptacle is placed to collect flying termites. Continuous beating and drumming on the ground around the hill trigger certain termite species to emerge to extract soldiers from the mound. Women and children push grass blades or parts of tree pods or the bark into the shafts of a termite mound or prepare smoke from charcoal from certain trees and blow it into the opening. Soldiers stripped into a container are then collected. Sometimes nests are dug up to collect queens

 

 

 

 

 

 

 

The Photo above: Fried Termites in West-Africa (by Pinterest)

In Benin, winged termites (Macrotermes falciger) are collected after the rain in a large pan containing water placed under an electric light. In the absence of grid-enabled light, lanterns are placed in large empty pans to trap the winged termites.

The queen is captured after the termitarium has been completely evacuated. The most favourable season for gathering and collecting insects in the wet months of May, June, and July.
There is a considerable trade in termites in some areas, and sun-dried termites are found at the right season in the local markets in many East African towns and villages. They are sometimes transported long distances to markets. The Baganda, who live around the northern shore of Lake Victoria in Uganda, use termites and fried grasshoppers as snacks between the main meals. In many Bantu-speaking parts of the country, boiled and dried termites are on sale in the markets at some seasons of the year. R.J.Phelps (in-depth pdf. Document), recorded that “Certainly dried caterpillars of saturniid moths are sold on the local market, and consumption of termites, locusts and tettigoniids by the clear majority of the population continues despite the presence of western cultures. In fact, many people of a European background eat termites, although not in the quantities that the local people do”

 

     + Other similar past Blog Post’s