The onset of summer rains in the southern African savannah lifts the arid landscape into a verdant paradise almost overnight. Among the many varied and astounding wonders of nature, this change signals the emergence of millions of squirming worms from egg clusters on the region’s mopane trees. These vividly coloured grubs immediately set about devouring the fresh green leaves of the trees which give them their name, much to the delight of predators like hornbills and starlings. But it’s not long before word of the mopane worm “outbreak” reaches the human inhabitants of the savannah too. Sacks, buckets, and tents are gathered, and entire families venture out into the woodlands, where they often camp for weeks on end, harvesting this vital source of sustenance and income.

Mopane worms, which are actually not worms but the caterpillars of the emperor moth, Gonimbrasia belina, are an integral part of the cultures that span the northern latitudes of southern Africa. Known as ‘amacimbi’ to Ndebele speakers, ‘matomani’ in Xitsonga, and ‘diphane’ to the Tswana, mopane worms are a cornerstone of heritage and nutrition in a climate where agriculture is challenging and rangelands for livestock are increasingly scarce.

Packed with iron, zinc, fibre, and three times more protein than beef, mopane worms are a free food source for anyone with access to communal land or even unfenced roadsides. And the weeks-long communal harvest is a much-anticipated event on the year’s social calendar, too. Kids, parents, and the elderly stick together for safety from wild animals, moving from tree to tree in chattering packs. After picking them off the trees, they take the worms back to camp where they are gutted, boiled in huge pots over open fires, and laid out in the sun to dry. The dried worms are stored for the rest of the year and commonly consumed in this form as a nutty snack, or reconstituted later into rich stews.

“For many poor households this is basically the last line of defense between access to protein and malnutrition,” says George Sekonya, PhD, whose research into non-timber forest products (NTFPs) delves into the mopane worm economy in southern Africa.

According to Sekonya, mopane worms hold a significant cultural and economic value in the region, bridging rural traditions and urban demand. Despite widespread migration from villages to cities across southern Africa, these caterpillars remain deeply rooted in cultural identity, fueling a thriving cross-border trade worth over $50 million annually. For many families still living in rural areas, dried mopane worms serve as both a vital protein source and a crucial income stream when sold to passing traders.

However, this increased commercialization puts undue pressure on mopane worm populations and threatens the marginalized communities that are heavily reliant on the summer harvests. Recent drought, coupled with habitat destruction due largely to settlement expansion, firewood harvesting, and detrimental mopane worm harvesting practices, exacerbates the issue.

Research by Sekonya and his colleagues indicates a classic tragedy of the commons, with ineffective governance and commercialization eroding established harvesting customs. Indeed, the enforcement of longstanding harvesting practices by tribal authorities across the extensive areas of communal land, tends to be less successful than on private land where access is limited, or on public land that is still for the most part effectively monitored by pre-existing conservation structures.

Harvesting complexities further complicate the situation. Gonimbrasia caterpillars undergo multiple larval phases, with the final solitary phase, Instar V, historically signaling tribal authorities to announce the start of the harvest season. This comes with reason, for by Instar V, the caterpillar is nearly ready to pupate and hence does not have much plant matter left in its intestines, making gutting easier. Simultaneously, waiting for caterpillars to reach this stage also ensures that a portion make it to pupation, from where they can re-emerge as moths to lay the next season’s eggs. However, increasing competition drives some harvesters to target immature caterpillars, disregarding the age-old traditional practices and resulting in less caterpillars reaching pupation and hence contributing to the next season’s outbreak.

These unsound harvesting practices may be a product of increased urban demand, as growing numbers of rural dwellers relocate to cities. But sales in unexpected sectors could simultaneously provide new opportunities to positively promote sustainable harvesting practices. Indeed, the recent but ever-expanding edible insect trend has not escaped South African foodies; and at least one South African entrepreneur believes its time the mopane worm took its place on the menu.

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

Similar to start-ups advocating the eating of other insects such as crickets, Matomani (which translates to “mopane worm” in Vesela’s native Xitsonga dialect) enhances the appeal of the mopane worm by incorporating it into protein bars and powders, while also encouraging customers to explore its culinary potential through a traditional Tsonga stew recipe utilizing whole dried worms.

Vesela envisions insect protein as a sustainable protein source for a growing global population and is dedicated to elevating insects as a whole past their current status as animal feed. However, compared to crickets raised on food waste, for example, she perceives the mopane worm as more akin to the “venison” of the edible insect spectrum. “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,” she says proudly, grinning ear-to-ear on a video call. “There’s nothing that is foreign, you know. It’s first-class protein.”

Vesela believes that instead of simply increasing the demand for mopane worms, social enterprises like hers can positively impact the regeneration of mopane worm populations and the habitats they depend on. In fact, the business idea itself was conceived when Vesela, joining harvests with her family, witnessed unsustainable harvesting methods first-hand. Now, Matomani has reached a place where it has the potential to directly impact how harvesting is done.

“We have a strict quality standard on our side, where we only buy Instar V worms from harvesters, thereby keeping harvesting sustainable and giving Instar V an opportunity to pupate and emerge next season,” Vesela says. These buying standards are in effect at Matomani’s facility in the regional hub of Phalaborwa, which serves as an important and reliable sale point for families dependent on mopane worms for their income.

While Matomani’s presence in the region has a positive impact on the rural economy and harvesting practices, there is always the risk that a rise in popularity of mopane worms in the trendy super food market could further stress wild populations as well as push prices beyond what rural consumers can afford. With insect nutrition predicted to play an increasing role in future human diets, it is quite likely that the “premium protein” of mopane worms will continue to elicit growing interest.

Based on his research, George Sekonya is cautiously optimistic that prices can be kept down under current circumstances, but believes widespread mopane popularization will probably necessitate structural change. “The risk would come if they (mopane worms) do become more popularized as a super food,” he cautions. “Then, farming of mopane worms would be the logical answer.”

Seemingly ahead of the curve, Vesela has plans in place for a pilot farming project, which she aims to launch alongside the seasonal mopane worm outbreak in late 2024. If successful, the production phase will involve mopane tree reforestation in the region, either to farm the mopane worms in situ, or to sustainably produce and harvest mopane tree leaves to feed the caterpillars at a climate-controlled production facility, much like commercial silkworm operations in Asia.

Until these farming methods are proven however, it would seem that mopane worms’ resurgence depends on all relevant authorities, harvesters, and entrepreneurs taking an integrated approach to managing this valuable resource. If they succeed, the insects have huge potential to thrive, empower communities that traditionally depend on them, and provide a sustainable, healthy protein source for a human population that is increasingly becoming more open to squirming, crawling protein on the menu.