Aussies on edge as number of nasties rises

CANBERRA: Australia's wild summer is unleashing new plagues of biting, stinging and swarming bugs and creepy crawlies.

Even in a nation famed for the number and variety of creatures out to make life miserable, floods and signs of a warming continent are starting to make the locals edgy.

From black clouds of flies and a surge in death-dealing spiders to fears that sharks are moving permanently in greater numbers to the shoreline, nature is biting back.

The humble fly - probably the least harmful - is becoming so pestilent that in Western Australia politicians are debating the cause amid concerns that tourists may be driven away from the wine and resort regions of the southwest.

Agriculture Minister Terry Redman has come under pressure to import new shipments of spring dung beetles, which eat the cow droppings in which flies breed. Redman has refused.

"It's my understanding that the last couple of years have had weather conditions that have promoted fairly substantial increases in fly populations, but there is no evidence to suggest that there's been any breakdown in the process of dung beetles responding to the cow manure that's around," he told ABC radio.

The same plague is driving central Australia crazy. There, heavy rain that ended one of the driest years on record has allowed farmers to stop dry feeding and put their cows on to fresh grass.

"The cows have been eating dry food and suddenly there's all this green grass, so they get a sort of diarrhoea and they produce this rich, sloppy dropping which is ideal for flies to breed in," researcher Peter Letz said.

In western New South Wales concern is rising at a huge rise in mosquito breeding as floodwaters recede and allow dormant eggs to hatch.

Westmead Hospital senior scientist Stephen Doggett told the North Queensland Register that the increase would lead to outbreaks of the debilitating Ross River fever, as mosquitoes pass on the disease from infected kangaroos and wallabies. He said that mosquito numbers would at least double, with further rains threatening to widen the risk of an epidemic and extending their lives to a week or more and increasing their feeding. This could reverse a downward trend in notifications of Ross River fever, which had fallen in line with extended drought, lowering antibody levels in humans and animals.

"The conditions are right for a pretty serious outbreak," Doggett said.

It is even more scary in Sydney, where reports have been pouring in of a surge in suburban snakes, spiders - including funnel webs and redbacks - and wasps.

Hot weather and ideal habitats from vast housing developments on the city's fringes have increased the danger from nasties such as brown and red-bellied snakes.

And Sydneysiders are being warned to watch carefully and protect their children from the potentially lethal funnel web spider, the aggressive black spider with a body of up to 7cm long that thrives in the region around Australia's largest city.

They like shady gardens, sheds, woodpiles and rocks, and often fall into swimming pools - where they can live long enough to bite anyone who tries to get them out.

Although they are known to have killed within 15 minutes of a bite, no deaths have been recorded since an antivenom was developed in 1981.

This is little consolation for Sydney.

An extended dry period and recent heavy rain is believed to have prompted a surge in numbers, noted by laboratories that accept captured spiders to milk for the antivenom.

And at the beach, commercial fishing, warming water and cleaner beaches appear to be encouraging more sharks inshore, although sightings have not yet reached the rash of attacks and scares of last summer.