Last updated December 4, 2017 at 4:50 pm
Cane toads on the leading edge of the invasion of Australia are bolder than their counterparts in more settled areas and are passing this boldness on to their young, researchers have discovered.
They raised two sets of cane toads in captivity. One set came from an area in Queensland where they have been present for 80 years, and the other from site in Western Australia where toads only recently arrived to see if the behavioural divergences observed in wild-caught toads were also evident in their offspring.
“Captive-raised toads from the invasion vanguard population were more exploratory and bolder (more prone to ‘risky’ behaviours) than toads from the range core, which suggests that these are evolved, genetic traits,” the scientists from the University of Sydney and Macquarie University wrote in the study published in the journal Royal Society Open Science.
The Queensland toads, by contrast, were shy, preferring to hide if given the opportunity.
Cane toads are devastating native wildlife and and researchers such as Rick Shine’s group at the University of Sydney have been studying their behaviour to understand how to control them.
Cane toads were introduced in the 1930s to destroy beetles in Queensland’s sugarcane crops, and that’s where things went terribly wrong.
They failed to destroy the beetles but spread rapidly and quickly adapted to the new environment. Despite being an introduced pest, cane toads are ubiquitous with Australian culture, from the roadkill to the croaks in the evening to the distinct pop when it’s hit by a car, even The Simpsons have made light of this.
Being able to see the behaviour in the offspring suggests that it’s not just external environmental factors that make bold cane toads but that genetic heritability plays an important part.
“A propensity to explore, take risks and engage with novel environments (neophilia) is likely to promote range expansion by stimulating dispersal,” the researchers write. “And these traits also enhance an individual’s ability to find water, food, shelter and mates in novel environments.
“Our study highlights the importance of behaviour as being potentially adaptive in invasive populations and adds these behavioural traits to the increasing list of phenotypic traits that have evolved rapidly during the toads’ 80-year spread through tropical Australia.”
It could be that part of the solution of controlling the cane toad populations may lie in their genes. Now that’s a bold solution.