Mauritius and Réunion's wee croakers appear to be rapidly evolving island dwarfs
On two islands in the Indian Ocean, the toads just aren’t what they used to be. Less than a century after their introduction by humans, the islands’ toads have shrunk in size by about a third.The finding, reported online November 18 in Biology Letters, potentially illustrates that “island dwarfism,”
“When you imagine insular dwarfism, you imagine this happening over thousands or millions of years,” says James Baxter-Gilbert, an invasion biologist at Stellenbosch University in South Africa. “But this [research] has the potential to show it happening in four orders of magnitude shorter timeframe, which is super exciting.”
Guttural toads (Sclerophrys gutturalis) are native to much of the eastern half of sub-Saharan Africa. Humans brought the toads to Mauritius — an island east of Madagascar, roughly 2,000 kilometers from mainland Africa — in 1922 to devour cane beetles. Just five years later, toads from Mauritius were brought to the nearby island of Réunion to control mosquito populations.
