A century after its discovery in 1925, the Wolkberg Zulu, a tiny butterfly fluttering on the brink of extinction, will be protected by law.
A conservation servitude — the first of its kind to be established for the protection of a threatened butterfly species in South Africa — has been registered on the farm in Limpopo where the critically endangered and endemic butterfly occurs.
The initiative which throws a considerable safety net over its fragile and dwindling population is thanks to landowner Gustav van Veijeren, who collaborated with the Lepidopterists’ Society of Africa and the Endangered Wildlife Trust. Work to establish the servitude was funded by Rand Merchant Bank.
The Wolkberg Zulu occurs on only two tiny sites at high altitudes in the Wolkberg mountain range. Intriguingly, the butterfly feeds on hard rock lichens, which are impossible to separate from the rock.
The idea for the conservation servitude was initiated by the Lepidopterists’ Society’s Dave Edge in 2021.
After three years of hard work, the Haenertsburg Wolkberg Zulu conservation servitude committee, spearheaded by Etienne Terblanche, the Custodians of Rare and Endangered Lepidoptera (Corel) custodian for the Wolkberg Zulu — worked with the landowner and the lepidopterists’ society to see the protective measure through.
The process was guided by a team from the Endangered Wildlife Trust, which funded the crucial legal support for the registration. The lepidopterists’ society initiated the Corel programme in 2011 to secure the survival of the country’s threatened butterfly and moth species.
The butterfly is no more than 25mm across from wingtip to wingtip — the wingspan when their wings are open is only about the size of a R5 coin. Apart from its diminutive size, what makes the species interesting is its flight.
“They’ve got this striking — especially if you’re a butterfly person — feeble little flight from one grass stem to the next. They just take it incredibly easy. Compared to other butterflies that fly boldly and fast and way up in the canopy, these little guys just fly low down,” Terblanche said.
“Their wings are whirring pretty quickly, there’s a lot of fanning, but they move slowly … from one grass stem to the next one. When you see that, it’s really endearing. It’s like, wow, you just want to protect them but that would hardly be fair to the butterfly.”
The species has other unusual habits for butterflies, such as feeding on hard rock lichens.
“Those lichens are almost as hard as a rock and that’s their food. They’ve got this funny looking urchin-like larvae, that really looks so weird and this thing chows on the rock lichen when it’s moist,” Terblanche said.
According to the lepidopterists’ society, the females lay their eggs on lichen-covered rocks, usually close to the ground. The lichen is also the larval food source, so when the eggs emerge, the larvae feed on the lichen during the night and probably spend the days hiding in cracks in the rocks. The flight period is from mid-December to early January.
“When the adults emerge from the pupae, then it’s energy-consuming time because it’s mating time but they can’t nectar-feed anyway. They actually live from the fats, gathered or built up from the larvae from those rock lichens. That’s amazing,” Terblanche said.
A recent discovery he made is that the females scent-mark tussock-grass blades. “And then she waits there for the males to come and do their thing and then she picks from among the best ones. They are way ahead in terms of gender and stuff,” he said, with a laugh.
“When you compare them, within their family and to other butterflies, those are unusual behaviours, which also makes them interesting and courageous.”
It is puzzling, however, that the lichens are so abundant yet “the butterflies are restricted to those tiny colonies”, he pointed out.
“There is an indication that their numbers have been dwindling, you might even say alarmingly so, so that if you were to think of it as a child, which I know is stretching it, but you do fall in love with them, they are kind of in the ICU it seems.
“In the Eighties, there were publications that indicated that, on a good day when the climate is just right, there would be hundreds of them flying around in that small area. In 2015, another publication talked about 20 to 30. Over the past five to six years, there’s been one occasion on which I’ve seen 10, maybe 20, and many occasions, seven or so.”
There are two caveats, he said. “One is they’re hard to find, they’re hard to see so there might be more … It’s hard to count them properly. Also for the reason that we don’t want to trample them into extinction by counting them. The other one is because they’re insects, they lay hundreds of eggs and they can bounce back.”
Their potential extinction is the hardest prospect to consider.
“Maybe it just doesn’t work out in the end. That would be an enormous loss. I guess a cynical person will say what role does it play … What does it really mean? It’s not so easy to answer but for me [the Wolkberg Zulu] is magical,” Terblanche said.
“The loss would be, for me, very intense. It has an intrinsic value or quality … If it disappears, will it make a major difference to a great many things? If diversity disappears, I think we will all basically go insane.”
The major threats to the species’ survival are agricultural activity, afforestration, inappropriate veld fires and invasive plant species.
Terblanche credited landowner Van Veijeren for the conservation servitude.
“As of today, there is a much better chance for future generations to enjoy and research this courageous little creature and its patch of critically endangered vegetation known as woodbush granite grassland. We are over the moon,” he said.
“I was quite amazed to discover many of our farmers really think about pristine nature; maybe it’s counter-intuitive but, on the other hand, they live close to it. What I hope this will do is help other farmers express their love for nature, so to speak, in this form and that little pieces, or a large piece, or an entire farm, can be conserved.
“Then we can build up a little mapwork of little pieces coming together. Let’s say, in the end, we’ve got a nice privately-owned corridor from the Kruger up to the mountains here … This might be the first little step in that direction.”
Few countries in the world have as many threatened and endemic species as South Africa, noted Ian Little, the conservation manager for the Endangered Wildlife Trust. “It is this amazing diversity of life that makes the job of conservationists here so very exciting and challenging.
“The formal protection of these unique and isolated habitats for these incredible species are the building blocks towards securing our natural heritage and the life-giving ecosystem services that are provided by these intact landscapes. We are proud to be the custodians of our unique and beautiful wildlife assets.”
The insects occur at only two tiny sites at high altitudes in the Wolkberg mountain range
