Madora (Sh), Macimbi (N)
Insects are often considered a nuisance and pests to crops and animals, but they can provide food at low (environmental) costs and generate income and be part of fighting poverty in rural areas. Edible insects and caterpillars constitute one of the cheapest sources of animal protein. Mopane worms, the larvae/caterpillars of the mopane emperor moth, are widely consumed in Southern Africa, a staple in rural areas and a delicacy in cities. They are collected from the wild and partly traded. Using small scale cultivation methods, families and villages could be provided with a source of cheap and sustainable food, and extra income.
Where they can be found:
Mopane worms feed on the leaves of the mopane tree (Colophospermum mopane). In Southern Africa, mopane tree areas stretch from northern parts of South Africa (Limpopo and Mpumalanga provinces) into Zimbabwe, Zambia, Botswana and northern Namibia. Although mopane worms feed mainly on the mopane tree, they are not limited to this diet, and can feed on many other trees that are indigenous to the same regions as the mopane tree, including the leaves of the mango tree. Thus the mopane worm is scattered over a fairly large area. In Zimbabwe, mopane worms are mainly found in the southern districts (Chivi, Mwenezi, Mberengwa, Beitbridge, Chiredzi and Gwanda).
What is harvested – Harvesting time:
Mopane worm outbreaks are seasonal. There is usually one main harvest per year, during the early months of the rainy season (November to January) but a smaller second harvest occurs in April-May following good rains.
Population numbers vary from year to year based on the availability of rainfall and presence of host tree leaves.
A preferred time for harvesting the larvae is when they are in the 5th larval stage, just before pupation. If they are collected at this time, no squeezing is required as the larvae empty their guts naturally before going underground. However the collecting window where there are enough on the ground to make it worthwhile is relatively brief and hence people collect prior to this. There may also be a certain amount of “we had better get there first” involved.
Average yield per collector:
Outbreaks of mopane worms, although seasonal, are timely in that they occur during the early months of the rainy season, traditionally referred to as the hunger season, when most rural households are in dire need of cash for food and school fees. Collectors can harvest between 25 and 50kgs of mopane worms per day. To avoid extinction, 10% of the worms should be left per tree for every harvest. Women and children take part in collection and sale of the worms. In recent years men have been involved, attracted by income-earning opportunities. Post harvest squeezing (removing of gut contents), parboiling and drying/roasting of mopane worms follow prior to selling at the market.
Wild outbreaks are unpredictable as they are influenced by a complex range of biotic (diseases and parasites), climatic and other factors that make harvesting and income undependable.
Mopane worm farming is a semi-wild practice and includes all stages from egg to adult moth production in a protected and monitored environment. Eggs are collected and stored till they hatch or they can be protected with chiffon sleeves on the tree. Once the eggs hatch into larvae, they need protection from predators and parasites by use of bird deterrents and shade cloth. Caterpillars can be moved from one tree to another if there is overpopulation or if the leaves have been depleted. When they reach the 5th instar, they are ready for harvest. Approximately 10% of the larvae should be left to perpetuate the cycle. Caterpillars can be transferred to pits for pupation. Prior to moth hatching, the pupae can be transferred into cardboard boxes where male and female pupae hatch. The moths can then be released at the base of a host tree under a shade cloth net. The moths lay eggs on the tree and the cycle can be repeated all over again.
Mopane worms are highly nutritious, comprising of70% crude protein, 16.70% crude fat, and 10.72% minerals on a dry matter basis.
- They are a cheap source of protein. They require only 3kg of feed to produce 1kg of worms; in contrast, cattle farming requires 10kg of feed to generate 1kg of beef. They also contain three times the protein content of beef by unit weight, and can be stored for many months.
- They contain significant amounts of phosphorus, calcium and iron. An adult’s requirements for calcium, iron and riboflavin can be met by consuming 15 worms per day.
- Mopane worms are also rich in (mostly unsaturated) fatty acids.
The processed mopane worms (degutted, boiled and dried/smoked) can be eaten as a crunchy snack or as a meal, rehydrated and fried or cooked in a spicy or peanut butter sauce, and served with sadza. Industrial processing is done by canning them. The Dzumeri Mopane Processing Centre (Dzumeri village, Limpopo province, South Africa) looked at developing various mopane worm products including flavoured snacks and a bread spread.
Mopane worms can be a source of protein also for livestock such as chickens, fish and pigs. The sun-dried mopane worms are milled and incorporated into feed as an inexpensive protein ingredient compared to more conventional protein sources.
Mopane worms are widely traded throughout Southern Africa (trading value of $85 million). Marketing chains extend from southern Zimbabwe and eastern Botswana to South Africa, Zambia and the Democratic Republic of Congo, as well as nationally within the main producing countries. In Zimbabwe the major outlets are supermarkets, bus termini, and open municipal and roadside/street markets. The price of mopane worms vary considerably among localities, selling points and with time/supply.
A key constraint of marketing mopane worms is the quality of the product which is often unhygienically prepared and not sufficiently dried for long term storage. An improvement in processing methods would address the constraints of sanitation and product quality, and also provide opportunities to investigate value addition.