Redbacks happy to make a home here

The Australian Redback spider. Photo / Supllied

Australian redback spiders could spread in this country because scientists have found the poisonous pests can survive in damp conditions and mate with native species.

By using climate and vegetation models, AgResearch arachnologist Cor Vink found that redbacks could settle in moderately wet, urban areas as long as they had shelter.

The spider was most likely to be found in the arid climate of the wine-producing regions - Central Otago, Hawkes Bay, North Auckland and Marlborough.

The spiders have turned up in Auckland but only in "one-off" discoveries.

But Dr Vink said the spiders could spread to the Far North and as far south as Christchurch.

He also found evidence of cross-breeding between the redback and the native katipo, which is of the same genus.

Cross-breeding or a proliferation of the redback, which is larger and has stronger webs, could lead to the demise of the katipo.

"You could end up with katipo becoming extinct by hybridisation - it would no longer be katipo any more, it would be a mish-mash."

Redbacks were first found 30 years ago in Wanaka and New Plymouth and are believed to have come ashore from cargo ships.

The remains of endangered beetle species had also been found in redback webs in Alexandra and Cromwell.

They are shy, but have a neurotoxic venom and a bite that causes severe pain to humans.

"I'm told it is unbelievable pain, like having strips of skin torn off you," said Dr Vink.

The pain, which usually came on half an hour after a redback bite, did not respond to the usual pain medication.

BAD BITE

Australian redback
*First found here in 1980.
*Females are the size of a large pea and males are bigger.
*Females: black body and red stripe, males: black and white.
*Venom causes severe pain but not death.

If you find a redback:
*Do not touch with bare skin.
*Place spider in a jar, and place that in freezer.
*Or crush the spider with shoe.
*Call the MAF exotic species hotline 0800 80 99 66.