Edible Caterpillars in Bas Congo
Number 8 - November 2005
Edible caterpillars and their food plants in Bas Congo, Democratic Republic of Congo
The Jardin Botanique de Kisantu is involved in a project to implement sustainable resource use of edible caterpillars in Bas Congo. There is an urgent need to reduce destruction of vegetation, mostly led by a need to make charcoal for profit. In fact, the profits earned from non-forest products can be higher than those from charcoal and the caterpillar project is being implemented to promote this and provide the information to the locals needed to make a successful trade in the caterpillars. The project will protect vegetation, useful trees and caterpillars in the region of Kisantu.
Caterpillars are an important traditional source food in Bas Congo and can provide much needed protein to the usual diet. Most families find it difficult to get enough protein form other sources. Fish and meat are generally too expensive. Hunting has cleared out most of the larger animals from the bush and even many of the smaller animals, such as the cane rat. Even caterpillars have become scarce in some areas.
The trees the caterpillars feed on have been cut down for charcoal, or the grass in the savannah burnt, thus killing many of the cocoons which often lie just below the soil surface. Instead of leaving some caterpillars to pupate and breed, all the caterpillars that can be found are usually collected. It used to be the custom that where two or more generations were known to be produced in a season, the first generation was left to pupate. The first crop of Ngala (Cirina forda) caterpillars, for example were said to be "for the birds".
Ngala or Ngahla
This savannah species is very much appreciated and is found early in the rain season from November to January in Bas-Congo. Probably as a result of overcollection and bush fires it is much less common than previously. It is widely distributed and eaten by people throughout sub-Saharan Africa. The eggs are laid in a large cluster around a twig of the food-plant Crossopteryx febrifuga. The caterpillars are often seen because they leave the branches bare. The stomach contents are normally removed before cooking because Crossopteryx febrifuga is toxic.
Elsewhere if caterpillars were found on branches of trees too high up for the collectors it was also traditional to leave them there, rather than cut the branch down. Unfortunately these safeguards are no longer respected in many villages.
A project was set up to conserve and increase the numbers of edible caterpillars by several villages involved with The Centre de Promotion des Technologies Appropries, a programme run by the Salvation Army at Kasangulu, Bas Congo. The project has involved the collaboration of many people and organisation including the Jardin Botanique de Kisantu and the National Botanic Garden of Belgium. Local people such as Tata Nganga, Captain Gracia Matondo and Tata Nsimba were instrumental in getting the project started.
In order to conserve and increase the numbers of edible caterpillars it is important to know how they live, what plants they feed on, and how to protect them. The caterpillars are rich in protein, can be sold at local markets, and protecting them helps to conserve the vegetation upon which they depend along with the whole ecosystem in the region.
This information has been gathered by Paul Latham into a manual about the caterpillars. With full colour photographs throughout, the 45-page PDF is available on CD now. Email Paul Latham for further information.
A project is currently underway at Kisantu and at another site to rear and identify the remaining unidentified species and a second edition is in the pipeline.
Francesca Saracco, who is assisting the redevelopment of Kisantu botanic garden, has recently engaged a biology student who is investigating the preferred caterpillar species around Kisantu and which trees the villagers particularly keep for rearing their own caterpillars. This will give an idea of tree species worth multiplying. It is likely that most use Acacia auriculiformis, an introduced species.
Collection, preparation, storage and palatability
Children are the main caterpillar collectors, though most people, while walking in the bush, keep a constant watch for them.
Frequently people will bring back young caterpillars and place them on trees near their homes where they can keep an eye on them. Many villages have a few Acacia auriculiformis trees planted nearby and these are used to rear the caterpillars of a number of species until they are ready to eat. Some farmers have taken this a step further and allow a proportion of caterpillars to pupate and frequently, for certain species, the resulting moths will lay eggs on the same or nearby trees. One farmer purchased Imbrasia forda larvae in the local market, introduced them to an area of savannah with plenty of Crossopteryx febrifuga and has been able to harvest the caterpillars regularly ever since.
A good knowledge of local plants is vital when collecting caterpillars. The gut contents of some of the larger caterpillars, e.g. Lobobunaea phaedusa and various Imbrasia sp., have to be removed, particularly if they have been feeding on so called ‘toxic’ plants (e.g. Crossopteryx febrifuga, Leptoderris congolensis and Millettia eetveldeana). Caterpillars are broken open or punctured and the green gut contents squeezed out. The white or brown matter is not removed. They are then normally boiled with salt and hot peppers until almost dry. Even though a number of species have spines these are not removed. The caterpillars are then eaten direct or cooked with peanut butter, or the seeds of pumpkin or sesame. They can also be cooked with cassava leaves. Nkankiti (Anaphe sp.) larvae contain a good amount of fat so can be fried without additional oil. Several species (e.g. Nkombo nseke) possess long hairs that must be removed before eating. This is usually done by singeing them off in a frying pan or on a hot metal sheet over the fire. The gut contents are then removed before the caterpillars are boiled as above.
Occasionally large enough quantities of caterpillars appear and are collected, boiled and dried for later use or for transport to distant markets. Minsangula caterpillars in particular, though not frequently found, may be collected in sackfulls when they do appear. Smoking is commonly used for large quantities, allowing caterpillars to be stored for up to 3 months. However the nutritional value is lowered and there is the danger that eating the caterpillars may cause cancer (Balinga et al. 2004).
An important edible caterpillar found in December and January. It is particularly rich in protein and can be eaten without removing the stomach contents. The food plant is Hymenocardia ulmoides.
Caterpillar life cycle
Caterpillars start life as an egg laid on a particular plant or tree. It is not difficult to find the eggs of the Ngala species because they are laid in a pile, like a tiny pyramid of white balls, on the new leaves at the end of a Kigala (Crossopteryx febrifuga) tree branch in December. However some species, such as Kaba (Lobobunaea phaedusa), lay their eggs singly so that it is harder to find them.
The eggs soon hatch out and the little caterpillars start feeding. Most moult or shed their old skins five times as they increase in size. Sometimes they change their colour too, like Makedi kedi (Bunaea alcinoe), which changes from brown to red and finally to black in its last stage. Certain caterpillars move down the trunk of the tree on which they have been feeding in order to moult, as is the case with Mvinsu (Imbrasia ertli). It is at this time that they are usually collected for eating.
When the caterpillar has reached its full size it climbs down and pupates in the ground. Certain caterpillars, such as the Nkankiti (Anaphe sp.), form a communal cocoon in the branches of a tree. Traditionally after taking the caterpillars, these sacks were used to keep gunpowder dry when hunting. Normally caterpillars should be disturbed as little as possible, especially when they commence to pupate.
For most species the cocoon remains intact until the start of the next rain season when the moth emerges, usually at night. After mating, the female moth finds a suitable food plant and lays her eggs before she dies. The male dies following mating.
A common small tree of the savannah. It is the only known food plant for Imbrasia forda edible caterpillars in Bas-Congo and is toxic to humans. The wood is hard, fine textured and durable and is used for making tool handles and for firewood. Bees visit the flowers for nectar in November.
Each species of caterpillar lives on certain plants. The Ngala (Imbrasia forda) is only found on Kigala trees in Bas Congo. The Mvinsu lives on Kimbaki (Funtumia africana), Kivinsu (Petersianthus macrocarpus), Kinzenze (Holarrhena floribunda) or Kingela (Ricinodendron heudelotii) trees. It is important that there are enough trees of the right kind to provide food for the caterpillars, especially those that only feed on one kind of plant. Where they are not present they can often be planted from seed, or young plants can be collected from below mature trees and transplanted.
Sustainable caterpillar harvests
Understanding the life cycle and the food plants utilized by each species will help in protecting and increasing the supply of caterpillars. Ngala (Imbrasia forda - see inset above) is a caterpillar which lives in the savannah and pupates just below the soil surface. During the dry season it is common to burn the grass in order to chase out small rats which may weigh less than 50gm each, but at the same time Ngala cocoons, capable of eventually producing far more than 50kg. of caterpillars, will have been destroyed in the process! If all the Mvinsu caterpillars are taken when they come down the tree trunk to pupate, there will be none left to produce next year's caterpillars. Traditionally the village chief decided when caterpillars could be collected. It is important that his authority is respected and that caterpillars are not taken at other times.
A tree of damp locations. It is the food plant for Rhypopteryx poecilanthes caterpillars. The wood is used for general carpentry and particularly for making boats, paddles and household utensils. It is resistant to insect and fungal attack. The bark produces a yellow resin which is strongly adhesive and water resistant. This is used for joining wood, attaching knives to handles and patching calabashes etc. It is also used to protect the feet against jiggers. The resin, bark and leaves have medicinal uses. The tree is often debarked for this reason in Bas-Congo and is now becoming scarce. Seed can be collected from the ground. Immerse in hot water and allow to cool over night. Seed should be planted as soon as possible, direct into the field, as the seedlings develop a long taproot.
It is important always to leave at least half the caterpillars on the tree to produce sufficient numbers for next season.
Caterpillars will not appear the following year unless some have been allowed to live and pupate this year. It is normal that many caterpillars will be eaten by birds, some will be killed by ants or by parasites. It is important therefore that enough are left to give a good harvest for next year.
A good place for rearing caterpillars is in a forest area which already has beehives. A good strong colony of bees will deter indiscriminate collecting of caterpillars and thus help to protect both the caterpillars and the trees. In this way a permanent reserve will be created where the caterpillars can be carefully managed. If possible it is best to have an area of at least l ha for this purpose. It may be possible to reserve a special area for the beehives for the whole village and this would also be a suitable for raising caterpillars.
A traditional "voka" or "nkunku" forest can also form an important reserve for caterpillars and these should be maintained wherever possible.
Caterpillars do not just appear suddenly from nowhere. Nor are they brought by the birds! We each can play our part in making sure that there will be enough caterpillars, plants, forests, and birds for our descendants, wherever we are in the world.
Kibungu Kembelo, Director of the Jardin Botanique de Kisantu, Bas Congo identified the food plants for many of the caterpillars and prepared herbarium specimens which have been lodged with Professor Malaisse, at the National Botanic Garden of Belgium, Meise. M. Kembelo and his staff also located a number of edible caterpillars to provide photographs.
A major output of the project is a reference Manual for the local people in the Kitandu dialect of Kicongo. This Manual has clear coloured photographs (some of which are reproduced here) of both the caterpillars and the food plants.
This article was adapted with permission from Paul Latham from the English edition of his manual 'Edible caterpillars and their food plants in Bas-Congo province, Democratic Republic of Congo (2005)' which was produced for two rural development projects run by the Salvation Army in Bas Congo, to improve the livelihoods of the local people. The 45-page manual is available on CD in PDF format. Please email Paul Latham for details.
Website of Luc Pauwels, Botanist specialising in the vascular plants of tropical Africa
Kisantu Botanic Garden on BGCI database