African Wildlife & Environment Issue 83

GARDENING FOR BIODIVERSITY

green colour and begin a new infestation. G. occidentalis , which makes an excellent replacement for this invader, often bears flowers and ripe fruit simultaneously, thus increasing its popularity with birds. At times Sombre Greenbuls (previously known as Sombre Bulbuls) and Greater Double collared Sunbirds virtually push each other off the same flimsy branchlet to get to their respective food sources, especially when the plant has climbed up high in the canopy of another tree. Confirming that insects are also very fond of this plant, an Olive Bush-shrike may sometimes be found working hard, collecting food for its screaming youngster, ever ready to be fed another juicy morsel.Where new shoots of the plant form a thicket, Southern Boubou and Bar throated Apalis take turns to stick their heads out of the foliage, vociferously announcing their presence. Many other insect-eating birds, such as Cape Batis and Cape Robin-chat (previously known as Cape Robin), also regularly visit these plants to investigate what delicacies are on offer. It is no wonder that G. occidentalis is so popular with insect eaters, for it is known to support the larvae of an amazing 19 species of moths. Some of these are intriguing, such as the spectacular Arrow Sphinx Lophostethus dumolinii , the largest of all our hawk moths. This huge brown moth, which has a wingspan of around 140mm, has a white arrow shaped marking, punctuated by a white dot, on each of the two forewings. Even the very large, pale greenish-yellow caterpillar is an attractive monster, sporting black spines sparsely arranged in longitudinal rows along its rotund body, and a prehistoric-looking ‘horn’ on the tail. These caterpillars are much sought after by some species of wasps, which lay eggs on

stem at the base of each leaf. Also, on the old stems one will find long, vicious spines clustered together to resemble sea urchins. The attractive flowers are white, cream or yellow and the fruit contain flat, black seeds distributed by birds and monkeys. Because the leaves and fruits are edible, containing high quantities of protein, iron and other nutrients, the plant is a popular vegetable in parts of Brazil. This vigorous climber completely destroys forest by growing up into the canopy and smothering trees. Although it is illegal to grow this alien invader, it is still used as a hedge plant by some less environmentally-conscious gardeners. This is especially true of the attractive golden-coloured variety but, unfortunately, when cuttings pruned from even this form are dumped, they revert to the natural The invasive Pereskia aculeata in full flower dominating, and eventually killing, an indigenous tree (Photograph P Vos)

Pereskia aculeata stem with short, curved spines at the base of each succulent leaf. On the right is an old stem with clusters of long, vicious spines resembling sea urchins (Photograph E Douwes)

33 | African Wildlife & Environment | Issue 83 (2023)