Eat Your Bugs!
Rob Toms and Mashudu Thagwana
 Insects are important as a source of protein as well as being traditional
cultural delicacies in southern African countries such as Botswana, Mozambique,
Zimbabwe, Zambia and South Africa. Mopane worms (caterpillars), locusts and
termites are well known as food insects, but many others are also on the menu,
including the edible stink-bug.
Stink-bugs are used in some cultures to add flavour to stews. In Venda they
are eaten for their own sake.The edible stink-bug Encosternum delegorguei (Heteroptera,
Tessaratomidae) known in Venda as 'thongolifha', is a useful winter harvest.
Unlike the mopane worm, or Mashonzha, which overwinters underground in the
subterranean pupa stage before turning into the mopane emperor moth, thongolifha
overwinter in the adult stage and never go underground. This means that the
fully grown thongolifha can be harvested in winter when there is little other
food available.
 In a group of 8 women collectors studied, it was found that the edible
stink-bugs are collected at dawn while it is cold and they are less mobile. As
the day warms up the bugs become extremely vigilant and fly away when disturbed.
In South Africa's northern province of Limpopo and in its eastern province of
Mpumalanga, the stinkbugs are harvested with naked hands and the defensive
secretions of the bugs causes a characteristic orange stain. In some other
regions the hands may be protected with a plastic bag. The harvested bugs are
collected in large woven plastic bags, such as those used for maize meal.
Preparing the meal
  The first step in the preparation is to separate all dead bugs, leaves and
debris from the live bugs. The live bugs are placed in a bucket and a small
amount of warm water is added before the bugs are stirred with a wooden spoon.
This causes the bugs to release their alarm or defensive pheromones. The
overpowering cloud of defensive secretions is so strong that it hurts the eyes
and the harvesters turn their heads away and close their eyes to protect them.
After a while, warm water is added and the insects are rinsed.
This process is repeated three times before the insects are boiled in water
and killed. If any dead bugs are accidentally left with the live bugs, it is not
possible for the dead bugs to release their defence secretions. These bugs can
be identified during subsequent quality control because their ventral surface is
blackened by the stink glands and they are rejected for human consumption. The
cooked bugs are then sun dried on an empty maize bag.
The preparation procedure above can only be used for live bugs, so an
alternative preparation is used for dead bugs. The heads of the dead bugs are
removed and the thorax and abdomen are squeezed between the thumb and index
finger. This causes a translucent pale green gland to be exuded through the neck
of the dead insect, and this is wiped off on a rock. The bugs are then boiled
and sun-dried as in the previous procedure. The dried
bugs may be eaten as snacks or sold at the markets. They can also be fried with
salt and a little water, until the water evaporates and then served with pap (mealie
meal).
Knowledge for sustainable harvesting
As is the case with the mopane
worm, knowledge of the biology of the insect is essential for
sustainable harvesting. The preferred habitat, food plants and life cycle are
all essential elements that need to be understood for successful sustainable
harvesting. The information on these aspects are limited and further research is
needed but our preliminary findings can possibly act as a pointer for further
studies.
The most favoured harvesting area in South Africa is in the northeast, at a
mountain outside Modjadji village near Duiwelskloof. This is interesting because
the collectors travel approximately 200 kilometres to do the harvest. When Rob
Toms and team first began to investigate the origin of this behaviour it was
found that harvesting at Modjadji is a new development and that they used to
harvest further west, in the area where the Sapekoe tea estates are situated, at
Magoebaskloof. This suggests that they are travelling to Modjadji because
environmental degradation caused by agriculture made their former harvesting
area unsuitable for the bugs. However, Magoebaskloof is also far from
Thohoyandou, so the original question is not answered. More research is needed
to find out why the harvesters travel about 200 Km to collect bugs but we
suspect that harvesting used to occur closer to the nearest big town,
Thohoyandou, home to the University of Venda, and that unsustainable harvesting
together with environmental degradation such as the development of tea estates,
which wipe out indigenous plants, are probably the main causes of these changes.
 At Modjadji the favourite food plant for the edible stinkbug in June is the
evergreen shrub Dodonaea viscosa Jacq. var. angustifolia Benth.
During our investigations we found that Dodonaea was regarded by the nature
conservation staff in a nearby cycad reserve as an invasive plant, even though
it is indigenous. The fact that Thongolifha appear to be feeding extensively on
Dodonaea suggests that this edible insect could be seen as a natural way of
keeping Dodonaea under control. In contrast, artificial control of Dodonaea will
almost certainly damage the thongolifha harvest. Further research on the
population dynamics of the insect and the host plant/s would be desirable.
Harvest after mating
As mentioned earlier, thongolifha have an incomplete metamorphosis. Unlike
the mopane worm, which over-winters in the chrysalis or pupa stage, Thongolifha overwinters in
the adult stage. The eggs are laid at the beginning of spring and the
development of the nymphs occurs in summer. We have found that adult stink-bugs
of both sexes are harvested in June, before the eggs have
developed. All adults collected at this time are removed from the gene pool and
excessive harvesting would not be sustainable. In theory it would be possible to
harvest the entire population without affecting the population by harvesting the
males after they have mated and the females after they have laid their eggs. In
practice this would require more information about the biology including exactly
when mating and egg laying takes place.
However, this may lead to a drastic reduction in harvesting time and it may not
be possible to harvest sufficiently to satisfy the harvesters.
Need for education
According to Toms, "During our research we have found that there is a
great need for better education. Last year we found that there was a need for a
poster on the life cycle of the mopane worm to bring indigenous knowledge
into the classroom and a poster has been produced. We have now identified a need
for a poster on sustainable harvesting of Thongolifha and are busy developing
one. Sponsors are needed to bring both these posters into the classrooms of the
Limpopo Provence where they have direct relevance. We also plan to get these
posters into classrooms in other provinces where they can serve as examples of
indigenous solutions to indigenous problems."
In the study of the harvesters, it was found that 7 out of 8 are pensioners
aged from 60 to 70. The youngest member of the group was an unemployed woman
aged 50. As part of a project on cultural and medicinal uses of insects, this
work has been funded by the National Research Foundation (NRF) since 2001.
More information:
Please contact: Dr Rob Toms at the Transvaal Museum, South Africa - toms@nfi.co.za
Related Links:
- Mopane
worms
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