Ladybird beetles - Coccinelidae
Ladybirds are well known small rounded beetles. Colours vary from yellow to black and the body is often bicoloured or spotted. These beetles and their larvae are a bonus to any garden as they are predacious and feed on aphids, mites and other small insects. The female often lays her eggs on plants that are heavily infested with aphids. The eggs are to be found on the underside of leaves. The larvae are black with yellow or white markings and are often spiny. Larvae sink their sharp curved jaws into the bodies of the aphids and suck their juices. Many of the species form aggregations just before winter and migrate to the highest point on the horizon where they hibernate.
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The Ladybird beetles develop rapidly. The larva emerges from the egg 5 – 10 days after being laid. The larva reaches maturity within 2 weeks. Pupation takes place on the plant where the larva fed and the adult emerges from the pupa after 4 – 10 days. There are 8 Coccinelidae subfamilies in southern Africa. |
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The Sticholotidinae are very small beetles. Scymninae beetles are small and pubescent. These species feed on coccids (scale insects), aphids and spider mites. Nephus reunioni is predatory on the citrus coccid (Planococcus citri) and Cryptolaemus montrouzieri are predatory on various citrus mealy bugs. Hyperaspinae beetles are shiny black beetles with bright yellow spots. These species feed on coccids. Chilocorinae species feed on red scale (Aonidiella aurantii) on citrus. The Coccinelinae are large typical ladybirds that are always shiny and often have bright spots. These species feed on thrips and other small insects. There are species that feed on fungi too. Coccidulinae are elongate, pubescent beetles that prey on aphids.
Noviinae beetles are medium sized and rather flattened. The introduced Australian Rodolia cardinalis is an important controlling agent of the cottony cushion scale (Icerya purchasi) on citrus.
Epilachninae are large, pubescent beetles with 11-segmented antennae. All species are phytophagous and several are pests on agricultural crops. Both larvae and adults are phytophagous – the adults usually feed on the upper surface of leaves, while the larvae feeds on the lower surface. The larvae of Epilachninae can be distinguished from other ladybird beetles by the presence of long branched spines on the back and sides.
Herbivorous ladybirds can become pests on cultivated crops and vegetables such as potatoes, pumpkin, turnips, radishes, beans and spinach. The potato ladybird, for example, is black with yellow-orange markings and generally duller than predacious ladybirds. The larvae of this pestiferous ladybird can be distinguished from other coccinelids by the presence of long, branched spines on the back and sides.