Invasive Cane Toads Use Cannibalism to Improve Chances of Survival in New Areas

A team of researchers from the University of Sydney found that invasive cane toad tadpoles gave their species an advantage in Australia by eating native toad hatchlings. In their article published in Proceedings of the National Academy of Sciences, the group describes how they tested the willingness of cane toad tadpoles to consume their competitors and whether this gave them an advantage.

Researchers have been studying the behavior of invasive species in recent years to learn more about their adaptability and whether that might help some of them survive on a warming planet. In this new effort, researchers studied the cane toad, a species native to South America that was introduced to Australia in 1935 as a means of pest control. Since then, the population of cane toads in Australia has skyrocketed. Previous research has shown that native toad predators have not been able to overcome toxins in the skin of invasive species, leaving them to multiply with abandon. Previous research has also shown that toad tadpoles often catch and consume hatchlings of native toad species, reducing the number of rivals. In this new effort, the researchers wondered if the toads developed this form of cannibalism as a tactic to help them survive in their new environment, or if it was something they did in their homeland. To find out, they carried out a series of tests.

The first test involved capturing hundreds of toads in Australia and their native South America. The team exposed the two to hatchlings native to Australia and found that the hatchlings were more likely to be eaten by toads living in Australia. The researchers also tested them in another way: they set traps containing native Australian hatchlings, then counted how many Australian toad tadpoles were ready to enter the traps compared to those from America. from South. Data showed that Australian toad tadpoles were 29.5 times more likely to enter traps than those living in South America. Researchers suggest this shows that the invading tadpoles have developed an aggressive tendency to kill and eat a native rival species. A third test showed that invasive tadpoles grew faster than native tadpoles, giving them the ability to easily defeat native hatchlings.

The researchers suggest that their results indicate that cane toads developed cannibalism as a way to improve their chances of survival in a new environment and that it worked very well for them.

© 2021 Science X Network