The first summer rains in the southern African savannah transform the landscape from a brown dustbowl into a lively green paradise. Among other wonders of nature, this transformation heralds the emergence of wriggling masses of mopane worms (pronounced ‘more-par-knee’), which immediately set about devouring the fresh green leaves they’d laid their eggs on. News soon spreads. Villagers in the region gather their sacks, buckets and pots and head out into the woodlands, where they can remain for weeks collecting what has long been one of their most important sources of food and livelihood.

The mopane worm – so called because it feeds almost exclusively on the butterfly-shaped leaves of the mopane tree – is not really a worm, but in actual fact the caterpillar of a species of emperor moth, Imbrasia belina. Known locally as ‘amacimbi’ to Ndebele speakers, ‘matomani’ to Tsongas and ‘diphane’ to the Tswana, the worms are an integral part of the rural cultures that span the northern latitudes of southern Africa. During the early summer harvest time from November to December, entire families descend upon the mopane woodlands, often camping there for extended periods at a time. Men, women, and children move together from tree to tree, picking the multicoloured worms off the mopane leaves in excited, chattering groups. The worms are gutted one by one, after which they after boiled and sun-dried to eat later as crunchy, nutty snacks or reconstituted in rich stews.

“For many poor households this is basically the last line of defence between access to protein and malnutrition.” — George Sekonya PhD

In this underdeveloped region, where an unpredictable climate makes grazing livestock the only viable form of agriculture, the mopane worm is the cornerstone of nutrition. For anyone with access to communal land, it is a free source of food packed with iron, zinc and fibre, and three times more protein than beef. 

“For many poor households this is basically the last line of defence between access to protein and malnutrition,” says George Sekonya PhD, who has done a lot of his research on the mopane worm economy.

He says that there is increasingly high demand for mopane worms in the bustling urban centres of southern Africa. People may move out of the villages and into cities, but the mopane worm represents a strong tie to their culture and homeland. This urban migration has stimulated a lucrative cross-border trade in mopane worms worth more than $50 million a year in southern Africa. For many rural families in the region, the dried mopane worms are more than the staple source of protein; they often generate the only household income.

However, in recent decades — and in South Africa in particular — the number of mopane worms observed during the “outbreaks” or hatching periods has dropped, which has alarmed those who rely on the caterpillar. Declining harvests in years to come could cause devastating effects on marginalized communities who depend on the summer harvest for crucial nutrition and extra income. 

Sekonya and his peers suggested recently in the International Journal of the Commons that, besides habitat destruction and the climate crisis, the poorer and poorer hatching periods most likely result from a ‘tragedy of the commons’. While the costs and responsibilities of monitoring harvesting on public and private land in South Africa are usually absorbed by pre-existing structures designed to govern other natural resources, tribal authorities covering vast swathes of communal land are less able to uphold entrenched harvest customs. Novice harvesters attracted by the increasing commercialization of the mopane have further exacerbated the problem by eroding established harvest customs.

But it is once the caterpillar reaches its final and solitary phase, Instar V, that the chiefs traditionally declare the season open for collectors to descend on the mopane forests. 

In this context, delving deeper into the human-caterpillar relationship and the complexities of harvesting is particularly intriguing. 

Once hatched at the onset of the summer rains, the Imbrasia caterpillar sloughs its skin four times, once between each ‘instar’ — the larval phase. The earlier instars are more gregarious, meaning in theory they would be easier to harvest. But it is once the caterpillar reaches its final and solitary phase, Instar V, that the chiefs traditionally declare the season open for collectors to descend on the mopane forests. 

At the Instar V stage the mopane is nearly ready to pupate, which means there is much less plant matter left in its intestines and it is therefore easier for harvesters to gut the caterpillar. It also ensures that a good number of Instar V caterpillars make it to pupation, from where they can re-emerge as moths to lay the next season’s eggs. 

Competition is increasing however and it is causing some harvesters to ignore age-old customs and to instead target the immature Instar III and IV caterpillars. While unsound harvesting practices may in large part result from growing urban consumption and increasing commoditization, sales in new sectors could help stamp out the practice. 

Urban consumers normally accustomed to eating mopane worms have until recently driven the rise in demand. But in the past few years, global trends have led the surge in demand as eating edible insects has become more popular, including among South African foodies. For one South African entrepreneur, it’s time the mopane worm took its place on the menu.

“I see it as a premium product. It's a delicacy and it's something that we are ready to share with the world,” says Wendy Vesela. Vesela founded Matomani, a start-up offering mopane worms as a “high protein alternative for a healthy diet with a low impact on the environment”.

Much like start-ups that promote other insects such as crickets, Vesela’s Matomani brand — which translates to ‘mopane worm’ in her native Xitsonga dialect — makes the mopane more appealing by packaging it into protein bars and powders, and also encourages customers to try their hand at a traditional Tsonga stew recipe using whole dried worms. Vesela is passionate about transforming insect protein into something more than an animal feed and instead into a viable, sustainable protein source for the expanding global population. But unlike crickets that are farmed on food waste, Vesela sees the mopane worm more as the ‘venison’ of the edible insect range.

“I want to be able to work with the communities and with the current tribal authorities, to be able to say, you know what, let's educate the communities. We have this valuable product and we need to look after it for the sake of the environment and future generations to come.”

“I tell people that the mopane protein is premium. It's natural, it's organic, it grows in the wild and there are no pesticides. There's nothing that is foreign, you know. It’s first-class protein,” she says through a beaming smile on the Zoom call.

Vesela is contagiously optimistic. She believes that instead of simply adding to the demand for mopane worms, social enterprises like hers can help regenerate mopane worm populations. She grew up going on harvests with her family in the Limpopo province of South Africa, and in between stints living abroad in Switzerland she returned to participate in several harvests. After she saw the poor harvest practices first hand, Vesela started to think about a sustainable business model. Her vision is to put mopane worms on the world stage as a sustainable alternative protein source, while also contributing to the replenishment of Imbrasia stocks in the wild, so that they could continue providing for the communities that depend on them.

“I want to be able to work with the communities and with the current tribal authorities, to be able to say, you know what, let's educate the communities. We have this valuable product and we need to look after it for the sake of the environment and future generations to come.”

Vesela has plans to reforest a 20-hectare piece of land and conduct a pilot project to see how best to increase the mopane worm outbreaks in subsequent years. She is also investigating whether it is possible to “domesticate” mopane worms in much the same way as silkworms are farmed, to ease the pressure on the communal mopane woodlands and to repopulate areas with lower mopane worm outbreaks.

“You create a great environment for them to thrive and you harvest a certain percentage of what is there, and let the rest go back so that next year you know there is more,” she explains.

Sustainability projects like Vesela’s can offer dynamic solutions to replenishing mopane worm populations. However, with insect nutrition predicted to play an increasing role in human diets in the future, it is likely that the “premium protein” of mopane worms will continue to elicit growing interest. If done badly, popularizing a resource that’s vital to marginalized households could exacerbate existing supply issues, in which rising demand is fuels overharvesting of the already dwindling mopane stock. Should demand and prices rise even higher, it is unlikely the wild harvested populations will be large enough to maintain a sustainable supply.

Based on his own research findings on non-timber forest products, Sekonya seems cautiously optimistic under current circumstances, but believes structural change would be required if eating mopane worms became commonplace.  

“I think that as long as the resources are easily accessible in the wild, the prices can be kept down. But the risk would come if they (mopane worms) become popularized as a super food,” he cautions. “Then, farming of mopane worms would be the logical answer.”

It is very hard to chart the mopane worm’s future, as the interplay of economics and tradition, of customs and the call of commercialization writes a complex story with no neat endings. The tale of edible mopane is still very much in the larval phase; not quite ready to emerge.

Protecting and regenerating the mopane population requires the authorities, harvesters and social entrepreneurs to co-operate to manage this valuable resource. An equitable mopane worm trade can empower and sustainably support communities that traditionally depend on the mopane. And as our expanding global population opens up to seeing some mopane magic on the menu, it could offer a vital source of healthy protein.