TERMITES
by Dave Rushworth
Termite mounds - often called 'ant hills', are one of the outstanding features of
many of the African savannah areas. They occur around the world in warm areas and
vary in size, up to several metres in height. The colour of the mound depends on
the soil type. Too frequently these mounds are considered, merely as a good source
of clay soil for patching roads or surfacing tennis courts. They are of much greater
value to the environment and deserve more respect.
Termites - often referred to as 'white ants' - are not related to ants; they are
more closely related to cockroaches and are one of the most primitive forms of animal
life. Termites colonies are the oldest known examples of communal living, far outdating
those of ants, wasps and bees. There are hundreds of different types of termite and
different species are adapted to various habitats. Africa, south of the Sahara, has
a greater variety than elsewhere. There lives are well documented and there are numerous
references from which one can gather further information. Human communities could
learn a lot from the way termites function.
TheIsoptera are divided into various families. They each have differing methods of
operation. You will have noticed large mounds, small mounds, 'workings' up trees
and walls, 'workings' across the surface of the ground and 'nests' inside old logs,
timber structures and clipping of grass and other vegetation. Termites - excepting
one family - are blind and vulnerable to desiccation and predation so they need to
create a clay covered environment - dark, humid tunnels and shelter along which to
travel and within which to work.
You will often observe a healthy tree growing out of a living termite mound where
it has been used to help support the mound.
It is important to understand that termites 'eat' only dead vegetation - they will
not destroy living trees (although they may 'eat' dead bark) - apart from one family,
the Hodotermitidae - or 'harvester termites' - which will clip grass and small vegetation
which they bury underground as a food supply. Healthy veld can withstand their ravages
where they are part of the normal nutrient cycle but veld in poor condition will
be laid completely bare. They don't cause the problem - they highlight the problem
and one should not be tempted to eradicate them. It will only make things worse.
Just accept the warning and conduct better veld management practices.
There are only a few species of termite that are a real nuisance to wooden construction.
These are of the family Kalotermitidae -the 'dry wood' and 'house' termites. They
don't build mounds and normally live in small colonies in dead logs. Some are only
able to live in damp wood. These species need to be controlled if one is to survive
in Africa. The word 'termes' means 'The End' !! The 'dry wood' termites help recycle
the nutrients locked up in old wood in the veld. The real threat comes from the imported,
alien termite Cryptotermes - or 'house termite', which now occurs around the southern
hemisphere and was accidentally brought in from the Caribbean. Like most aliens,
they need eradication as they have few natural controls but be sure you have the
right culprit. In any case be very careful when using residual poisons as you could
easily kill all the birds and other animals that might feed on the dead termites.
Plain diesel is a good non-toxic treatment, where practical.
There is a small family - the Rhinotermitidae, with a short 'snout' on the head of
the 'soldiers' from which they secrete a defensive fluid. These termites construct
an underground chamber but no mound. They are 'damp wood' termites and construct
tunnels on the soil surface to reach their food source which consists of various
plant matter. There are some 'imported' species and they can be destructive to timber
construction in mainly arid areas.
TheTermitidae - are by far the largest family, containing about 80% of the species
within our region. Most of the species in the other families mentioned 'digest' their
food with the aid of bacteria in their stomachs. The majority of the species in this
family collect food and store it in cones or 'fungus gardens' where the material
(cellulose) is broken down by fungus which provides digestible food for the termites.
Genera in the family Termitidae include the Macrotermes, which construct the conspicuous,
tall mounds of soil displaced from workings very deep down below ground level ; -
the Microcerotermes, which constructsmall, subsurface 'nests' ; - the Odontotermes
which construct underground nests with protruding ventilation shafts from a large,
gently rounded mound and which can be very destructive to buildings ; - the snouted
Trinervitermes, which construct the numerous small, rounded mounds in open grassveld
are 'harvesters' which work at night and are able to squirt a defensive liquid ;
- and Amitermes, which construct small, dark coloured mounds, often against rock
or other objects and which are also capable of emitting a defensive fluid.
Each of the hundreds of species of termite have an important role to play in nature.
They are a prime source of food to other animals; they all recycle nutrients that
would otherwise remain locked up ; and they create 'islands' of nutrients that support
many other plants and animals that benefit from the fertile, moist conditions. In
sandy regions, which cover much of the country, nutrients are leached out of the
soil by water and carried down to levels out of reach of grass and other plants.
The only things that can retrieve these nutrients to the surface are deep working
termite mounds and deep rooted trees. Many of the early prospectors analysed the
soil in large termite mounds to indicate the minerals deep down in the area. Next
time you consider destroying a termite mound for any reason remember that you are
also destroying one of nature's valuable deep mineral pumps.
