Faster, stronger, longer: accelerated evolutionary change in the cane toad

Professor Rick Shine, an ARC Australian Laureate Fellow from The University of Sydney, is undertaking important research focussed on protecting Northern Australia’s peak predators, snakes and lizards, from invasive pest species, such as the cane toad.

Recent research undertaken by Professor Shine and his team has shown that the annual rate of progress of the cane toad invasion has increased five-fold since their introduction into Queensland in 1935. Cane toads expanded their range by about 10km a year during the 1940s to 60s, but are now invading new areas at an expedited rate of over 50km a year.

By attaching radio transmitters to the toads, their research found that toads with longer legs move faster and are the first to arrive in new areas. They also found that toads at the front have longer legs than those in older (long-established) populations. These long-legged toads also had more endurance, travelling about half a kilometre further in a three-day period.

The research demonstrated that these changes in a toad’s body shape, its behaviour, dispersal ability and tactics are heritable. That is, offspring resemble their parents, even if they have been raised under standard conditions.

These findings indicate that evolutionary forces are likely to fine-tune organism traits in ways that facilitate more rapid expansion of the invading population, and that control efforts against feral organisms should be launched as soon as possible, before that invader has time to evolve into a more dangerous adversary.

	Professor Shine was awarded the 2016 Prime Minister’s Prize for Science for his work using evolutionary principles to address conservation challenges.

 

Image: Cane toad yellow. Image courtesy: Matt Greenlees / The University of Sydney.