Original article published in ENVIRA (Winter Edition 2021), quarterly Newsletter for the Unit for Environmental Sciences and Management at North-West University (UESM).
By Marlize Muller & Wynand Muller, Forb Ecology Research Group (FERG).
In the Limpopo Province of South Africa, nestled among pine plantations on the R71 road between Polokwane and Tzaneen en route to the Kruger National Park you will find a small village called Haenertsburg. This village is next to the largest remaining remnant (~192 ha) of the critically threatened Woodbush Granite Grassland (WGG), home to around 661 plant species, 237 birds, 62 mammals, 38 reptiles, 11 amphibians and an unknown number of invertebrate species (Niemandt & Greve, 2016). Some of these invertebrate species are butterflies, including the Wolkberg widow (Dingana clara), the Wolkberg blue (Orachrysops regalis), the Wolkberg russet (Aloeides stevensoni) and the Wolkberg Zulu (Alaena margaritacea). The Wolkberg widow, Wolkberg russet and Wolkberg Zulu are endemic to the WGG and will likely go extinct if the WGG disappears.
The Wolkberg Widow is classified as endangered as its distribution is limited to only the Wolkberg area of Limpopo. The species has a shiny slate brown/ground colour with orange and black markings on both sets of wing edges and a size ranging from 56 mm to 65 mm. They have a sailing/fluttering flight pattern low to the ground among bushes and rocks and their preferred habitat is on rocky slopes among protea bushes.
The Wolkberg russet has been declared critically endangered as only a few colonies are known to exist. However, a new site, where the Wolkberg russet seems to flourish, was discovered in 2019, namely in the Bewaarskloof Reserve (Terblanche, 2020). The species has a velvety brown colour with pale markings/spots on its dorsal side, while the underside is lighter in colour with more distinct markings/spots and a distinctive orange patch under the forewing. Their size ranges from 56 mm to 65 mm and they prefer to fly low and slow near the ground in large colonies.
The Wolkberg Zulu has a beautiful mix of burnt orange and black markings while its underside is white with a netted black pattern. Their size is in the range of 24-30 mm. The species is under threat from alien tree plantations and is critically endangered. Eggs are laid on rocks or on the ground, the larvae are hairy, slug-shaped, well camouflaged and feed on cyanobacteria. The pupae are also hairy and hidden in rock crevices and leaf debris.
For these three butterfly species, the plants they are dependent upon for food (larval and adult) are not yet fully known. There is therefore much to still learn about these species before the grassland system is lost due to silviculture, urban development (Niemandt & Greve, 2016) or bush encroachment from the adjacent savannah biome. Two trusts are working to conserve these three butterfly populations, namely the Brenton Blue Trust and the Endangered Wildlife Trust (EWT). There is also a volunteer group, Friends of the Haenertsburg Grasslands (FroHG) that actively works to conserve the grassland. Anyone can become a member of these groups to promote the conservation of some of the most threatened ecosystems and species.
Next time you are visiting the Haenertsburg-Magoebaskloof area, be sure to go on the Louis Changuion hiking trail and try to spot some of these endangered butterflies in Limpopo’s most threatened ecosystem!
All species descriptions were obtained from Woodhall, 2020.
Acknowledgements
Many thanks to Etienne Terblanche, “An African Butterfly Guy” for his expertise on the butterflies of the Haenertsburg Area, his photos and his great love and passion for butterflies.