Fear and bacteria: Possible ways of controlling the cane toad

12 Jun 2008

Scaring cane toads and targeting their bacteria are two control strategies that will be suggested by a Queensland scientist at today's (June 12) Australian Vertebrate Pest Conference in Darwin. 

Professor Rob Capon from the Institute for Molecular Bioscience at The University of Queensland presented the findings of a two-year study that charted the chemical ecology of the Australian cane toad. 

“Our studies have revealed for the first time a range of potential control strategies that could selectively target and reduce the survival of cane toad eggs, tadpoles and adults,” Professor Capon said. 

Together with Professor Rick Shine and his team at the University of Sydney, the UQ researchers led by Professor Capon are close to identifying an alarm chemical in the cane toad tadpole. When exposed to this chemical, the tadpoles become scared and flee, only to undergo premature metamorphosis (transformation into a toad), resulting in underweight toadlets with a lower chance of survival. 

“Once this alarm chemical is identified it could be developed into a non-toxic, biodegradable and species-specific product that could be used in controlled waterways during the breeding season to stress the toads and lower the numbers that are produced in successive generations,” Professor Capon said. 

The study also revealed for the first time the relationships between cane toads and bacteria. Another strategy to be presented by Professor Capon involves targeting these bacteria, which are capable of transforming and chemically diversifying toad toxins. Chemically diverse toxins are more effective against a wider cross-section of predators, which enhances toad survival. 

“Our studies suggest that bacteria impact cane toad ecology in other ways, by influencing behaviour in egg laying and in protecting eggs from infectious disease and predation,” Professor Rob Capon. 

“The relationship between cane toads and bacteria may be the weak link, and by exploiting this weakness we may be able to halt the cane toad invasion of northern Australia.” 

The study examined all life stages of the cane toad, analysing toxic and hallucinogenic chemicals and alarm pheromones in the hope of finding a way to minimise the toad's impact on fragile Australian ecosystems. 

Media contacts: 

Professor Rob Capon - 07 3346 2979

Bronwyn Adams, IMB Communications – 07 3346 2134 or 0418 575 247