Mopane Worm

Probably the best known insect food of Africa, the mopane worm, is a large edible caterpillar that forms the basis of a multi-million dollar trade in the Limpopo Province, Mpumalanga, Botswana and Zimbabwe.

The mopane worm is a large caterpillar that feeds on the mopane tree, Colophospermum mopane. The adult stage is a large and attractive Emperor moth (Imbrasia belina - Family Saturnidae). The worm is an important source of protein and income to many people. However, the trade is threatened by over-harvesting, and mopane worms are now rare or extinct in some areas where they were once common.

The mopane worm is one of southern Africa’s economically important insects, with great potential for quick development, but would however depend on sustainable utilization. If enough worms (e.g. 10%) are not left to produce eggs for the next season the mopane worm industry will continue to decline.

Transvaal Museum

Mopane Worms are still a valuable crop

In the early 1980s, annual sales of mopane entering commerce were estimated by the South African Bureau of Standards to be 1600 tons; this did not include those privately collected and consumed (Dreyer and Wehmeyer, 1982).

The Yansi people of central Zaire are not atypical of other indigenous groups, and the importance with which they regard their caterpillars is indicated by some of their sayings:

'Caterpillars and meat play the same role in the human body'

'As food, caterpillars are regulars in the village but meat is a stranger' (Muyay, 1981).

One person can pick about 20 litres per day if the bush is rich in caterpillars, the value of which in 1985 was K20. Thus 7 days' picking should give Kl40 if all are sold and this is a month 's salary for a general worker in Zambia. Not strange that people travel 200-300km to pick caterpillars. And traders come from Lusaka and the Copperbelt (900 km) to buy the foodstuff and sell it at a much higher price when they go back.

Insects as Human Food

Links: See

Paul Latham's descriptions of insect food in the Bas Congo.

40% of all animal protein eaten there is caterpillars.

In the Congo, Imbrasia ertli moth caterpillars climb down the trunk of the Funtumia tree each time they moult. They can then be gathered for a scrumptious lunch.

Photos - Paul Latham

In parts of sub-Saharan Africa, edible caterpillars can be quite abundant—averaging as many as seven pounds of processed insects per tree. The sight of caterpillar frass on the ground and chomped leaves on trees are clues commonly used to track the insects. In the Democratic Republic of the Congo, people call out to Minsangula caterpillars (family Saturniidae), saying "hey, hey" until the caterpillars respond to the noise by jerking from side to side, revealing themselves to their hunters.

Women and children are the primary caterpillar collectors. When some caterpillar species mature, they form large processions and descend down the tree trunks, so harvesters simply pluck them off the trees. Caterpillars are so important to the local diet and income in the Central African Republic that women move to the best harvesting areas with their children and set up huts for two months (usually Dember-January) each year.

Some people even "farm" their own caterpillars. Paul Latham, a retired Salvation Army agriculturist who has

been interested in edible insects for over 20 years, met one man from the Democratic Republic of the Congo who has cultivated a backyard population of the black, red, and yellow Ngala caterpillar (Cirina forda) from caterpillars he purchased in the village market.

Villagers there plant Ricinodendron heudeloti trees to attract Mvinsu moths (Imbrasia epimethea) to lay their eggs for easier harvesting later on.

Traditionally, some cultures have observed strict societal rules surrounding caterpillar gathering to make sure populations survive from year to year. A Bas Congo custom directed people to harvest only one of two annual caterpillar generations, leaving the second "for the birds," according to Latham, and caterpillars on high branches were generally left alone. But some people cut whole branches or trees down to collect heaps of caterpillars at once. This practice could ultimately lead to the decimation of the forest and may become a bigger threat if human populations and poverty increase.

Insects as Human Food

A lepidopteran that was considered a food delicacy by the Aborigines was the witchety grub. Although different source suggest different names for this insect, the larvae of (Endoxyla leucomochla Turn) is the true witchety grub of the Aborigines. Witchety grubs (larvae) are found in the roots of Acacia bushes, commonly known as the witchety bush in central Australia. These grubs were the most important insect food of the desert and were a much valued staple in the diet of the Aborigines-especially women and children. Men also loved the grubs but would seldom dig them.

The grubs were collected by digging up the roots and chopping them up to obtain the grubs within. The grubs can be eaten raw or can be cooked in ashes. Cooking causes the grub to swell and their skins to stiffen. Cooked witchety grubs frequently have been likened in taste to almonds. The larvae are rich in calories, protein, and fat. Ten large grubs are sufficient to provide the daily needs of an adult.

An example of mass harvesting of edible insects is the moth feasts that occurred in the Bogong mountains of New South Wales. The Bogong moth, Agrotis infusa, aestivated in large numbers every year in rock shelters of these mountains. From November to January, hundreds of Aborigines from different tribes would gather for huge feasts on these adult moths. Rock crevices were covered with layers of these moths, which were collected by dislodging and then collecting the moths from the cave or crevice floor.

Moths were then cooked in sand and stirred in hot ashes, which singed off the wings and legs, then sifted on a net to remove their heads. In this state, they were generally eaten, although sometimes they were ground into a paste and made into cakes. As a food, the Bogong moth was rich in fat, with the average fat content of the male's abdomens exceeding sixty-one percent and of females, fifty-one percent of their dry weight.

Although the Aboriginal diet was generally low in sugar, honeypot ants were a highly valued food that provided a source of sugar for the Aborigines of central Australia. Workers of the honeypot ant (Melophorus bagoti Lubbock and Campanoyus spp.) gather honeydew from scale insects and psyllids, and feed it to other workers, which become mere nectar storage vessel with greatly enlarged abdomens. The helpless replete ants, which regurgitate some of the nectar when solicited by other workers, are kept safe in deep underground galleries. The ants were obtained by scraping the surface of the ground to find the vertical shaft of the nest that led down to horizontal chambers where the honeypot ants were located. Vertical shafts may be dug down to almost two meters.

Another popular source of sugar in the aborigine's diet was the "honeybag" (hive) of stingless native bees (Trigona spp.). To locate the honeybag, the Aborigines caught a bee feeding on pollen, and after attaching to it a leaf or petal by means of sticky juices of certain plants, let it go. The bee would fly straight to the hive and the item it was carrying not only would make it easy to see, but would result in its flight being lower and slower, thus, it was easily followed by the hunter. Also, when looking for honey, Aborigines watched for small black lizards, which often lived in honey trees and fed upon the bees as they returned to the hive. To obtain the honeybag, a tree could be cut down or, if the tree were large, a hole could be cut in the tree under the hive. A stick could then be poked into the hive and stirred about until the honey ran down the stick into a bark basket.

Australian Aborigines by Dr. Ron Cherry

But Are Grubs Good Grub?

Testimonial

Even George W Bush likes caterpillars - once, when asked his favourite childhood book, he named Eric Carle's The Very Hungry Caterpillar.

The mere fact that it was published some decades after Georgie officially became an adult is by the way. Georgie is not known for absolute truthfulness.

The book describes the development of an increasingly voracious caterpillar, from egg hatch to metamorphosis into a beautiful butterfly. In addition to the character appeal of the larva and aesthetic quality of the illustrations, the book teaches some valuable lessons about the nutritional ecology of insect herbivores. The caterpillar hatched on Sunday: on Monday he ate through one apple, on Tuesday two pears . . . and on Saturday "he ate through one piece of chocolate cake, one ice cream cone, one pickle, one slice of Swiss cheese, one slice of salami, one lollipop, one piece of cherry pie, one sausage, one cupcake, and one slice of watermelon. That night he had a stomach ache! But he was becoming more American by the day.

Insects in Archaeology

Africa has more than its fair share of tribulations, and swarms of hungry locusts are not the least of them.

The hominids that lived in South Africa 1.8 million years ago, known as Australopithecus robustus, were traditionally thought to be vegetarians, chomping coarse plant matter with their large, flat teeth and powerful jaw muscles. But now, a microscopic analysis of bone tools found in two South African caves suggests that termites were high on their menu. The conclusion fits with other recent evidence that suggests Australopithecus had a protein-rich diet.

Francesco d'Errico of the Institute of Quaternary Prehistory and Geology in Talence, France, and paleoanthropologist Lucinda Backwell of the University of Witwatersrand in Johannesburg, South Africa, looked at high-quality replicas of the world's oldest bone tools: 85 pieces from the caves of Swartkrans and Sterkfontein, found close to the remains of Australopithecus robustus. Using microscopes and image resolution software, they examined scratch marks on the bones.

The scratches on the bones belie scientists' earlier belief that they were used for tuber-digging, the team reports. Bone tools created by other researchers show angular marks when used to dig for tubers. The Australopithecus tools, in contrast, had striations running parallel to the bone's axis. This pattern closely matches the marks found on experimental bone tools used exclusively for opening up termite mounds. In addition, the marks reflect abrasion by fine-grained sediment--like the dirt that makes the hard outer crust of a termite mound. The authors say they also have circumstantial evidence that termites were available: The rock layers that contain the tools also include the fossils of several species of termite-eaters.

The study is consistent with carbon isotope evidence from Australopithecus bones, which suggest they enjoyed a varied diet including either grasses or meat and perhaps insects (Science, 15 January 1999,), says Stanford University anthropologist Richard Klein. "The only thing that bothered me," says Klein, "is that the termite nests I've seen might require a steel chisel."

"Current consensus (before the research detailed above) holds that the 3-million-year-old hominid Australopithecus africanus subsisted on fruits and leaves, much as the modern chimpanzee does. Stable carbon isotope analysis of A. africanus from Makapansgat Limeworks, South Africa, demonstrates that this early hominid ate not only fruits and leaves but also large quantities of carbon-13-enriched foods such as grasses and sedges or animals that ate these plants, or both. The results suggest that early hominids regularly exploited relatively open environments such as woodlands or grasslands for food. They may also suggest that hominids consumed high-quality animal foods before the development of stone tools and the origin of the genus Homo.

Isotopic Evidence for the Diet of an Early Hominid Matt Sponheimer, Julia A. Lee-Thorp Science Jan 15 1999: 368-370

Many palaeoanthropologists of the Skull & Bones Club have jumped on this as evidence that hominids were hunting or scavenging big savannah game as long ago as 3 million years. But termites also ate carbon-13-enriched foods.

Skull & Bones Club

And, as Susan Crockford complains: "The authors...offer only insects (termites) or the young of grazing bovids as possible choices. What about snakes that consumed grass-eating rodents, or the rodents themselves? What about insect-eating amphibians or small primates? Have we become so fixated on late hominid big-game hunting skills that we can consider no other prey items for their ancestors?

Termites apparently are well worth all the trouble. d'Errico and Backwell say nothing beats them as a source for protein, fat, and essential amino acids--as well as calories. While a rump steak yields only 322 kilocalories per 100 grams, termites are good for 560 kilocalories.

Science Now

See Backwell & d'Errico's full paper.

Pat Shipman, who originally analysed the bone fragments 10 years earlier, and concluded they were digging-sticks, has so graciously reviewed the work by Backwell and d'Errico that outshone her own endeavours, that I am quoting it almost in full:

"Some 10 years ago, Brain and I examined high-fidelity replicas of the apparent working ends of 69 possible bone tools from hominid-bearing layers at Swartkrans and Sterkfontein, dated to between 1.8 million and 1.1 million years ago, using the scanning electron microscope. We found and photographed clear use wear on these pieces that was closely confined to the tips and that differed from the rounding and smoothing produced by a variety of natural agencies, suggesting that these objects were indeed bone expediency tools. Based on very limited experiments using similar pieces of modern bone, we suggested that the wear on these fossil bone tools best matched that on bone splinters or horncores that had been used in digging tubers in the rocky soils surrounding the South African cave sites. In our view, these objects were a bony equivalent of a digging stick, a very useful object in a region short on trees.

Backwell undertook a much broader taphonomic study of all 23,000 specimens from Swartkrans, which resulted in the identification of 16 additional long bone fragments with apparent use wear, bringing the sample of purported bone tools to 85. As an aid to interpreting the various taphonomic agents that had affected different parts of the entire sample, she also studied 35 reference collections of fossil and modern bones of known history. These reference samples included a total of more than 13,000 bones modified by 10 nonhuman agencies (hyena, dog, porcupine, leopard, cheetah, river gravel, spring water, flood plain activities, wind, and trampling) and bones used experimentally in digging bulbs and tubers, piercing and scraping animal hides, and breaking into termite mounds to induce swarming of the inhabitants.

Somewhat surprisingly, Backwell and d'Errico showed that there was a statistically meaningful difference between the orientation of the scratches produced by digging for tubers and those created during opening up of termite mounds. The orientation of the scratches as well as the nonmetric aspects of use wear on the fossil specimens very closely resembles the pattern seen on termiting tools. Thus, Backwell and d'Errico are able to conclude with considerable confidence that early South African hominids used pointed bones, horncores, and bone fragments to catch and presumably eat termites, a rich source of protein and fat.

What can you do with a bone fragment?

Chimp eating termites from his own termite catching tool.