Good Bugs For Your Garden

In a garden where creatures are free to prey on each other, the biological cycle plays out dramatically. If you see these critters around your garden, know that they are beneficial to your garden’s ecosystem.

1. Praying mantis

Mantids can camouflage themselves so well in surrounding vegetation that you’ll fail to notice them. With their compound eyes on a large head that can rotate 180˚, they can however see very well (anything from 2 – 15m) and will use their powerful legs to catch prey with lightning speed, just like an unsuspecting fruit fly.

They use their mandibles to eat their prey alive and are also cannibalistic, eating each other if not mating. Birds, bats, spiders, snakes and frogs make a meal of these interesting insects named for their folded forelegs held closed together as if in prayer.

Diet: Flies, beetles, moths, crickets and aphids.

2. Rain spider

It takes a tough cookie not to scream in fright when a rain spider drops from a lush creeper at an open window onto a bed. It is a fearsome-looking, but harmless creature in brown or grey with a leg span of up to 100mm. The female keeps her eggs in a sac made from leaves bound with silk and will guard them protectively until the spiderlings hatch.

It is only when extremely provoked that she might bite a gardener – which is not at all poisonous and feels like a bee sting. Rain spiders are preyed on by birds and pompilid wasps.

Diet: Crickets, geckos, cockroaches, moths and other large insects.

3. Ladybird

Many a poem, nursery rhyme and story has been written in honour of the lunate ladybird which is brightly marked in black and yellow or red. This dome-shaped aphid eater hibernates in rotten logs and under rocks in winter and becomes active in spring and summer once its yellow eggs have been laid close to a food source, to enable the larvae to start playing their important role of controlling aphid populations.

Ladybirds have interesting habits such as ‘playing dead’ or excreting a foul-tasting fluid from the joints in their legs to discourage predators which include birds, frogs, wasps, spiders and dragonflies. They also have the ability to fly far and high at a swift speed.

Diet: Aphids and scale insects.

4. Dragonfly

Dragonflies – with their huge eyes – share excellent sight ability with the mantids. The adults are energetic day-time predators using their aerodynamic bodies and gossamer wings to hunt for small insects. Their prey is chased down, held fast between bristled legs, and eaten in flight if a safe place to land is not available. They are, in fact, such busy little insects that even mating is completed while in flight.

Eggs are laid in water or on the leaf of a water plant. The larvae will remain in the muddy sediment of a body of water for a while, quite happy to feed on aquatic life, and will in turn be the prey of fish, frogs and water spiders – good reason not to clean a rustic pond too often.

Diet of adults: Midges, mosquitoes, flies, beetles, moths, butterflies, each other and almost any other insect they can grab.

5. Golden orb-web spider

The female golden orb-web spider has impressive black and yellow body markings (like artful tattoos) and can reach a size of 14cm. Her domain is an intricately woven, silky golden web which can be in excess of a square metre. In this web, she catches a variety of insects, which are wrapped in silk before being paralysed with her poisonous fangs – a killing method which is not at all harmful to humans. A bite is nothing more than a little rash or redness.

The male orb-web spider is minute and also present in the web, but normally in a spot where the female cannot reach him to eat him. Birds, lizards and bigger spiders will prey on her.

Diet: Wasps, grasshoppers and other flying insects.

Sources:

The Garden Guardian’s Guide to Environmentally-responsible Garden Care by Johan Gerber. Aardvark Press Publishing, 2006. ISBN 0-9584785-5-4.

Attracting Wildlife to your Garden in Southern Africa by Roy Trendler. Struik Publishers, 2005. ISBN 1-77007-064-8.