Bioengineered cannibal toads may help combat an invasive species in Australia

• Scientists in Australia are developing genetically modified “Peter Pan toads” that remain in their tadpole stage and die before reaching adulthood. They aim to reduce the population of invasive cane toads.
• The modified tadpoles are more aggressive, consume up to three times more cane toad eggs than normal tadpoles and also eat hatchlings of their own species.
• However, large-scale deployment faces hurdles due to the labor-intensive gene-editing process, among other issues.

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Scientists in Australia are exploring the use of genetically engineered cannibal toads to combat one of the country’s most damaging invasive species. The cane toad was originally introduced from South and Central America in 1935 to manage agricultural pests, but they have since spread across northern Australia, where their population now exceeds 200 million.

These animals have caused significant ecological harm by poisoning and outcompeting native wildlife. Their presence has contributed to sharp declines in local snake, lizard and marsupial populations and forms part of Australia’s broader $25 billion per year invasive species problem.

Can these new toads help the problem?

To address the issue that cane toads present, researchers are developing bioengineered toads that never reach maturity. Referred to as “Peter Pan toads,” these genetically altered animals live for several months, remaining in their tadpole stage until they die before becoming breeding-able adults.

Additionally, while cane toad tadpoles are already known to eat their own species’ eggs, the modified variants consume up to three times more eggs than normal tadpoles. The bioengineered tadpoles are also larger and more aggressive, with studies showing they can eliminate entire batches of newly laid eggs. Researchers hope this behavior could reduce cane toad populations in their breeding grounds, stopping the problem at its source.

What are the challenges of using genetically modified toads?

However, scaling up this potential solution to the problems posed by cane toad species remains difficult. The gene-editing process is labor-intensive, requiring individual modification of thousands of eggs. Additionally, since the engineered tadpoles never mature, they cannot reproduce, complicating efforts to sustain their use over time.

What happens next?

Despite these challenges, the Northern Territory government of Australia has expressed cautious support for the concept, stating that it is open to the approach as long as it does not pose risks to native wildlife.

Pending the results of a risk assessment, field trials are planned for later this year in the state of Western Australia. That study will examine potential effects on non-target species, including fish, turtles and birds that share habitats with cane toads.