HERALD SUN (Melbourne, Australia) 15 October 07 Cracks in march of the toad (Annalise Walliker)
It's hard to take pity on a cane toad, but many of the hopping horrors are suffering sore backs, according to Australian scientists.
It's not from too many whacks with the golf club, but rather too much hopping, a world-first study into cane toad health has found.
Fortunately for Victoria, the toads' newly developed health problem and our cooler climate mean the ugly toads may not make it to Victoria for a long time yet,
Toads used to hop 10km a year but are now travelling up to 60km a year in places around the Northern Territory, researchers at the University of Sydney and the Department of Primary Industries found.
The strain on these larger toads' bodies meant a high number were developing severe spinal arthritis, Prof Rick Shine said.
"We found that around 10 per cent of toads had arthritis in their spines," he said. "Ironically, factors that have contributed to the toad's rapid spread across the continent have also rendered it susceptible to arthritis."
The two main causes are the toads' bigger, longer legs, which put stress on their spines, and the running down of their immune systems, so they cannot fight soil bacteria that speeds up the development of arthritis.
Luckily, the combination of bad health and Victoria's current unsuitable climate means they may not arrive for another few decades.
"The closest population to Victoria is on the north coast of New South Wales, but hitchhikers frequently turn up in Victoria," Prof Shine said.
"They're not going to make it under their own steam now.
"But the toads are adapting to be good little Aussies, and they may well be able to cover these areas we think are too cold and too dry. But it's going to take decades."
South American cane toads were introduced into Australia from Hawaii in 1935 to wipe out cane beetles. Instead, they became a voracious invader.
Prof Shine, professor of evolutionary biology at Sydney University, leads a Darwin-based project studying where the toads are likely to spread.
Earlier this year he said it was only a matter of time before they spread south to "certainly a very large area of southwestern Australia, around Perth and that whole corner of the continent, a big southern swathe down through Adelaide and western Victoria, and then some patchier spots along the NSW coast, heading down towards Sydney".
His latest findings will be published in the online Proceeding of the National Academy of Sciences journal this week.
http://www.news.com.au/heraldsun/story/0,21985,22584980-2862,00.html?from=public_rss

AUSTRALIAN BROADCASTING CORPORATION 15 October 07 Spinal disease may hold back toad invasion
Scientists have made an intriguing discovery that could help the fight to eradicate cane toads.
They have found the fastest toads leading the westward invasion across Australia's Top End - the ones with the longest legs - have a remarkably high incidence of spinal disease.
And they are hoping with a bit of biological engineering they can take even more spring out of their step.
Biology professor Rick Shine says the toads' fast-paced spread could help bring about their demise.
"What we discovered is that there's a real cost to that behaviour, and that the toads at the invasion front have got a remarkably high frequency of spinal arthritis," he said.
Professor Shine says scientists in Darwin recently stumbled on a peculiar phenomenon: that the fastest, fittest toads - particularly the ones with the longest legs - often have huge lumps on their backbones.
He says this suggests that those toads leading the invasion are developing serious spinal problems.
"It's sort of the mathematics of evolution: any individual that slows down gets left behind," he said.
"The only animals you get at the invasion front are the ones that are the descendants of the ones that went fastest, who in turn are the descendants of the ones that went fastest.
"So it's a cumulative process where any characteristic that enables toads to go quicker and quicker ends up at the invasion front, and it reaches the stage where it's pushing the toads' body plan about as far as it can go.
"So we start to see these rather horrific spinal problems developing."
Professor Shine says the discovery is bolstering hopes that with a bit of biological tinkering, the toads could at least be slowed down, if not reduced in number.
"The arthritis is partly driven by a soil bacteria; normally it's all over the place, and it normally doesn't cause any problems except for people who have got immune problems," he said.
"It looks like the toads' immune system is under such pressure that they're actually now vulnerable to attack by these otherwise very benign bacteria.
"And that kind of gives us a hint that maybe the toads' immune systems are a real Achilles heel that we might be able to exploit in looking for ways to control cane toads."
Professor Shine says researchers are now looking at a worm parasite that afflicts older toads and frogs, to see if it can be developed against the wider toad population.
"We've taken a relatively simple-minded ecological and behavioural approach - the idea being that rather than jumping out there trying to kill toads, maybe the first step is to try to understand them," he said.
"Maybe with a better understanding of the ecology of toads we'll get a much better position to work out how to control them."
http://www.abc.net.au/news/stories/2007/10/15/2059576.htm

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