The Mopane Worm -
Indigenous Knowledge in the Classroom
R.B. Toms, M.P. Thagwana and K.D. Lithole
If you enjoy game viewing, you will know about the "Big Five", but
many will not know the "Big Twelve". Meet the mopane worm - one of the
"Big Twelve African insects."
"mopane worm" Imbrassia belina is probably the most important
insect in southern Africa from a cultural point of view. Here it is well known
as either Mashonzha, Masonja or Amasonja. It forms the basis of a
multi-million rand trade in edible insects, providing a livelihood for many
harvesters, traders and their families. However, the industry is not without
problems. Droughts devastate the harvest on a regular basis and there are areas
where overexploitation has led to local extinctions.
Dr Rob Toms and team at the Transvaal museum in South Africa set out to find
just how much local communities and harvesters actually know about these edible
delicacies and whether it is enough to save this 'golden' worm from extinction
in certain areas. They stumbled across some myths, some truths and devised an
ingenious plan of using this worm as a valuable teaching tool.
Meet the meat
mopane worm has a complex life cycle in which there is complete metamorphosis,
or what is known as "holometabolous". The eggs are laid by a large and
attractive moth, with a name to fit, the mopane emperor moth. Small worms hatch
from the eggs and moult a few times before they reach maturity, the stage most
sought after for harvesting. The worms that are not harvested leave the trees
and pupate underground. The life cycle is completed when the adult moths emerge
from the pupae, mate and lay eggs. If the cycle
is broken at any point by excessive harvesting, for example, it will not be
possible to maintain a sustainable harvest.
Mopane worm in schools
In research conducted in the Limpopo Province, Toms, Thagwana and Lithole
soon established that there were many people, including school science and
biology teachers, who simply did not know the life cycle of the mopane worm.
They found this alarming because harvesting Mashonzha without knowledge of the
life cycle is a bit like trying to farm maize without knowing that it is
necessary to plant seeds.
discovered that the concept of sustainable harvesting is not practised according
to basic scientific principles and that traditional myths still play a strong
role in determining harvesting strategies for Mashonzha. Moreover, the mopane
worm played no role in school education, an opportunity lost.
Myths - scattering the ashes
There is a myth that if young Mashonzha are harvested the older individuals
will leave the area. According to another myth, when larvae leave the trees and
burrow into the ground they are going to die.
In fact, the purpose of digging into the ground is to pupate, and this is
essential to complete the life cycle. If the larval stage is thought to end in
death, and is not seen as part of a life cycle, there is no reason to conserve
the worm at this stage.
While most people surveyed had no suggestions of how the mopane worms could
be reintroduced into areas where they had been over-harvested, the rest
suggested scattering ashes. There is a myth that the ashes from the fires used
to prepare worms for the market could be scattered in areas where the worms are
extinct in an appropriate ritual. According to this legend, this will bring the
Recolonising the mopane worm
Natural re-colonization in fact can only be a slow process, because the moths
only live for two to three days and must complete their reproductive processes
in this time, leaving little time for dispersal. The only other stage with any
dispersal potential is the worm or caterpillar stage where dispersal can only
occur slowly over limited distances.
For natural dispersal to be at all effective it would need the assistance of
local communities who are aware of the process and can place an embargo on
harvesting in sensitive areas. Managed re-introductions could also be possible
in certain areas, however this would not work without the support and
co-operation of local communities. Without this support relocated insects would
soon be harvested, providing a very expensive meal for a few people.
According to Toms, to manage a reintroduction it is necessary to identify at
least one stage in the life cycle that can be reintroduced.
and relocation of eggs could work, but the time frame for this is limited.
Relocation of larvae may be the most practical and the Mopane woodland project is gaining valuable experience investigating the controlled
rearing of larvae in captivity. The collection of pupae in the field would be
difficult and expensive and collecting moths would not be recommended because
they are fragile and only live for two to three days. Eggs and larvae are
possibly the best stages to relocate, but further research is needed in this
Competing with browsers
Many farmers are cashing in on the mopane worms, charging large amounts of
money to mopane worm harvesters to use their land. There are some farmers however who
manage fenced in browsers who view the worms with concern as competitors
for the mopane tree leaves. They can rest assured - the worms are highly
seasonal, so even if defoliation does takes place, the worms will never be
present for long and regrowth of leaves will take place once the worms are
harvested or have pupated. This process can result in the regrowth of fresh new
leaves for the browsers. Farmers, it seems, could also do with a bit of
education. Good management based on knowledge from research and indigenous
knowledge and a sound relationship with the local harvesters, which allows for
the planned removal of a controlled number of worms at an appropriate time, not
only solves the problem of over utilisation of the trees by the worms, but also
ensuring survival of the worms and a regular income from their harvest.
Domesticating the mopane worm - the way forward?
way of developing the mopane worm resource is to investigate the possibility of
a silk-worm like industry where domesticated Mashonzha are raised on leaves
harvested from domesticated mopane trees. One of the advantages of moving in
this direction is to make the industry less unpredictable, because it is
strongly affected by environmental conditions such as droughts. A disadvantage
of this approach is the cost of the research and the cost and difficulty in
transferring the benefits of the research to the poorest of the poor. For a
domesticated industry to succeed on a small scale and be accessible to the
poorest of the poor, the cost of production will be have to be compared with the
cost of wild worms or dried worms at the market. However, knowledge gained in
experimental domestication trials are also potentially useful to efforts to
optimise the wild crop. In areas where re-introductions are needed, knowledge of
rearing and sustaining the larvae will be of great value in keeping them alive
during the capture, transportation and subsequent release.
The mopane worm is one of our most spectacular well known insects and was
chosen as one of the BIG
12 African Insects. Toms and his team at the Transvaal museum believe that
this worm has great potential to be used as an icon in the teaching of
indigenous knowledge, sustainable harvesting, conservation and food security.
The Transvaal Museum has produced a poster on the life cycle of the mopane
worm and is making this available to schools. The poster emphasizes the
importance of leaving some larvae to complete the life cycle is emphasized. It
teaches learners that, it is more important to think about how many worms must
be left behind than to think about how many can be harvested.
As a project on cultural and medicinal uses of insects, this work has been
funded by the National Research Foundation (NRF) since 2001.
For more information please contact: Dr Rob Toms at the Transvaal Museum,
South Africa - firstname.lastname@example.org