Cane toad v cane toad: poison used against itself

THE SEEMINGLY INDESTRUCTIBLE cane toad may have a weakness after all.

Scientists say they have found the best weapon yet to eradicate cane toads from isolated areas – using the amphibians’ own toxin against them.

Rick Shine from the University of Sydney’s school of biological sciences said the system was already trapping tens of thousands of cane toad tadpoles, and could wipe out the toads from some areas.

“I think it is really exciting stuff,” Rick said. “In order to control toads you need to stop them breeding, and this new method stops them from breeding,” he said.

The technique relies on research that two years ago found that cane toad tadpoles were attracted to the eggs of their own kind.

The tadpoles probably sought out the eggs to kill off newly hatched tadpoles, which would otherwise compete for food, Rick said.

The researchers figured out the tadpoles found the eggs was via the toad’s venom. Once that breakthrough was made, Rick and colleagues quickly realised they could use the venom as a bait, which attracts cane toad tadpoles but repels native frogs.

Using funnels to trap cane toad tadpoles attracted to the bait, the scientists captured tens of thousands of young cane toads within a few days, and completely eradicated the toads from billabongs about 50m in diameter.

“It is only local and isn’t going to eradicate cane toads from Australia,” Rick said. “There are huge areas where it is just impossible to put traps in every water body.

But he said in high conservation areas it could dramatically reduce cane toad numbers and it was the best method so far to control cane toads in some places.

So-called stowaway populations of cane toads, which arrived somewhere by hitching rides on trucks or cars, would be vulnerable to the new technique, Rick said.

He nominated Hamilton Island, which has only recently been invaded by cane toads and an isolated population at Taren Point in Sydney, as areas the new traps could be effective.

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