A carnivorous frog with fabulous trousers has been devastating the native biodiversity of Southern Australia as it surges through the land snacking on just about everything as it goes. A new study published in the Australian Journal of Zoology describes how the invasive amphibian has established a population of more than 1,000 hungry frogs in Streaky Bay, having been spotted everywhere from the Eyre Peninsula to Adelaide airport.
What the spotted-thighed frog, Litoria cyclorhyncha, lacks in consideration it makes up for in style. Brown with green blotches when resting, the anuran’s blue-spotted pattern is revealed when its legs are extended. Native to Western Australia, this invasive species appears to have hitchhiked its way across the Nullarbor to Southern Australia. Arriving in their droves, the frogs are “an indiscriminate eating machine that will devour just about anything it can fit into its mouth,” according to ecology expert Christine Taylor in a statement.
This study is the first into the spotted-thigh frog’s diet in its newly claimed territory, the findings of which will contribute to a valuable body of work exploring the impact of alien species on native ecosystems. The results so far indicate that the spotted-thighed frog’s destructive eating pattern spells bad news for the indigenous species of Southern Australia, as it could destroy food webs in outcompeting species of native birds, reptiles, and mammals.
“As it eats away at local species, it’s impacting the natural ecosystem, which can displace or destroy local food webs, outcompete native birds, reptiles and mammals for resources, and potentially change natural biodiversity,” said Taylor.
The study saw researchers sift through the stomach contents of 76 invasive frogs gathered from three habitats. They found that on average the frog’s stomach contains six prey items, with the range of prey encompassing over 200 different species, 60 percent of which were beetles, spiders, and insects. It also revealed the frogs had been eating native geckos, mice, and even smaller frogs.
While an alien frog might not sound threatening, the infamous introduction of cane toads to Australia in the 1930s has served as a harrowing precedent to what can happen if such voracious carnivores go unchecked. The implications of the cane toad's introduction and invasive proliferation are still being felt now, almost 100 years later, demonstrating the severity of the damage caused.
“The spotted-thighed frog is obviously very mobile. Already it’s managed to travel more than 2000 kilometers and set up a colony in Streaky Bay,” said University of South Australia’s Associate Professor Gunnar Keppel in a statement. “But its considerable tolerance of salinity and potential ability to withstand high temperatures could lead to further geographic spread, and if not controlled, it could extend further eastward into the Murray-Darling Basin.
"Importantly, if you do see one of these critters in your travels – leave it be. We don’t want it hitchhiking any further.”