(Photo: University of Sydney)
Australia's reviled cane toads may have met their match in a native species of flesh eating ants, according to a study published last month.
The findings were welcomed by conservationists in Australia eager to rid the land of Bufo marinus, "one of the world's most successful invasive species," according to scientists at the University of Sydney.
The poisonous toads are vulnerable to attack by aggressive meat ants, scientists announced in the British Journal, Functional Ecology.
The report came after researchers observed the one-centimetre long predators attacking baby toads emerging from water.
"The meat ants send workers out from the colony; if they encounter a live baby toad they jump on it," Rick Shine of the University of Sydney told the Australian Broadcasting Company.
"The toad, rather foolishly, tends to just sit there and let itself be ripped to shreds and the workers then carry the bits of toad back to their colony," he said.
The bulky amphibians are vulnerable to the ants, Iridomyrmex reburrus, Shine says, because they haven't developed a fear of their attackers.
His team compared the juvenile invaders' chances against the meat eaters, with that of seven native frog species.
Baby cane toads happily sit out in open areas during the day, unlike native frogs that hide in the bushes, Shine explained.
Reaserchers also raced frogs under laboratory conditions and concluded that the unwelcome invaders were more vulnerable to ant attacks because of their shorter shins and more slothful gait compared to nimble local species.
The ants have not been seen attacking the nocturnal adult toads, which can grow into fat one-kilogram beasts that squirt lethal poison into mouths of larger native predators.
The toads have killed hunters such as crocodiles, snakes and rare marsupial carnivores, and have seriously threatened the balance of native ecosystems, according to researchers at the University of Sydney.
"The ideal way to control toad numbers would be to find a predator that kills and eats toads but leaves native frogs alone," Shine said.
Meat ants are common around tropical pools and streams, according to the Brisbane Times, but the next question is whether they can offer practical help in the battle against the destructive intruders all over Australia.
"The idea would be that we might be able to encourage the meat ants to forage a bit closer to the water's edge during the times when the baby toads are emerging or perhaps even build up ant colonies closer to the edge of the water," Shine said.
But unleashing a new bio-weapon against the intruder is no light matter, he warned.
"We'd obviously have to be pretty careful about that; the story of the cane toad itself is a great example of biological control gone wrong.
The well-documented story of the cane toad in Australia started in 1935 when 101 toads from Hawaii were imported into Queensland for pest control against scarab beetles on sugar cane plantations.
They quickly multiplied to 60,000 in a captive breeding programme before they were released into cane fields, according to BBC science and nature.
Females can lay up to 35,000 eggs at a time, unleashing a plague of Biblical proportions that has reached an approximate population of 200 million today, according to the Canberra Times.
The noxious pests have steadily hopped westwards from Queensland for the past 50 years, with the first toads crossing the Northern Territories boundary into Western Australia earlier in March, according to the Brisbane Times.
“Even slight increases in mortality rates [of cane toadlets] might cause significant reductions in cane toad populations in Australia,'' the study says.
No comments:
Post a Comment