The Pine Emperor Moth (Nudaurelia cytherea) is one of the largest moths in Southern Africa, but it is the caterpillars that are especially impressive. Reaching some 10-12cm in length and almost 2cm in diameter, they are covered with a myriad of colourful spots that look like lights on a Christmas decoration. On account of this they are sometimes referred to as Christmas Caterpillars. However, their association with Christmas trees is a more sinister one, as they are a serious pest of pine plantations, defoliating trees with their voracious appetites. For the native fynbos though, this is great news as pine trees often escape and invade. Any animal that keeps pine trees in check should be greeted with open arms.
The Pine Emperor Moth is a native species and has adapted to eating pine trees but naturally feeds on a variety of native plants. The ones we found at Phillipskop were feeding on the Searsia angustifolia and Searsia tomentosa, members of the cashew family, Anacardiaceae. These are common shrubs of slightly richer alluvial and clay soils. They can defoliate individual plants but the shrubs are able to resprout and there is no long-lasting damage. Hopefully, they will also take out any pine seedlings that happen to appear as well.
The Pine Emperor Moth belongs to the family Saturniidae, which includes many of the largest moths in the world. It was at one time included in the genus Imbrasia, along with the Mopane Worm, the popular food of southern African countries. Both have now been moved into different genera (Nudaurelia and Gonimbrasia respectively). Like the Mopane Worm (Gonimbrasia belina), the Pine Emperor Moth caterpillar can also be eaten, though its popularity has never reached that of the Mopane Worm. Nevertheless, considering its size, it would make a substantial snack and rich in protein. (But having tried a mopane worm once and only once, I have no intention of testing this out.)
The adult moth of Nudaurelia cytherea emerges in autumn and like its juvenile form, is impressive in size. While less flamboyant in colour, mainly beige and brown, it has striking eye-spots on both fore and hind wings. The hind wing spots are the largest but often covered when at rest. When threatened, the moth can expose these eyespots and hopefully scare off any potential predator. The male and female moths can be easily told apart by their antennae. The antennae of the males are broad and feathery, whereas the female are fine and with only slightly teeth. This is because the male uses the antennae to detect the pheromones released by the females into the air. The moths are occasionally attracted to lit windows on moonless nights, when they can make quite a noise as they flutter against the glass.