Friday, August 22, 2008

On numbers alone, insects have taken over the earth. Australia boasts more than 85,000 different species, compared to just 250 types of mammal and around 750 kinds of bird. But, while many insects are unwelcome and downright annoying, not all of them are pests. Read our quick guide to discern friend from foe.

Strange but true

Female mantids are known to bite the head off the male while mating.

Stick insects can grow up to 25cm long, and can shed and regrow limbs.
Termites can live for 17 years or more.

Only male crickets ‘sing’. They do this by rasping one wing against the other. The male mole cricket has strong shovel-like forelegs, which he uses to dig a burrow with a specially-shaped entrance that amplifies his chirping.

The good guys

• Flies Sure, some species are rather irritating, but there are almost 10,000 types of helpful Australian flies. They aid our ecosystems by feeding on, and helping to decompose, rotting matter.
• Assassin bugs They’re killers, but in a good way. They trap and suck out the bodily fluids of other bugs, using their long, strong jaws. Introduce enough of them and they can clean out an entire infestation of unwanted insects.
• Ladybirds Not just a pretty face, the ladybird is a fierce predator of soft-bodied prey, such as aphids. A species of Australian ladybird saved the Californian citrus industry in the early 1900s by eating a potentially devastating pest known as cottony cushiony scale.
• Dung beetles These critters collect and bury dung to hoard food for their young – a process which directly incorporates nutrients into the soil. By competing with flies for food, they are also responsible for helping control fly population levels.

The bad guys

• Silverfish Endowed with an ability to digest cellulose, silverfish happily feed on paper and glue in our homes.
• Cockroaches Australia’s most common pest cockroach is the large American variety. It’ll eat just about anything.
• Earwigs They drive gardeners crazy by eating flower petals and fruit, but they also consume pests such as mealy bugs.
• Christmas beetles Yes, they herald the onset of summer, but, because they eat the leaves of eucalyptus trees, Christmas beetles are also serious pests. Their larvae can also kill grass by eating its tender stalks from underground.