KU Biodiversity Institute scientists recently announced the results of an extensive study of the genetics of the tree frogs in the Philippines. Their surprising results suggest that the Asian Tree Frog (known to biologists as Polypedates leucomystax and many Filipinos as Banana Frogs, or “Palakang Saging”) has spread throughout the Philippine islands in few centuries. Their finding of genetic uniformity throughout the Philippines suggests that humans have inadvertently transported these Asian tree frogs throughout the archipelago as “hitchhikers” or “stowaways” in agricultural shipments between islands by boats, ferries, and commercial shippers.
Biodiversity Institute herpetologists, in collaboration with the Parks and Wildlife Bureau of the Department of Environment and Natural Resources and the National Museum of the Philippines, published these findings in the international journal Molecular Phylogenetics and Evolution. Their results suggest that the extraordinary Philippine tree frog species P. leucomystax has expanded its range throughout the Philippines, aided by humans and the constant inter-island trafficking of sugar cane, bananas, copra, rattan, rice and other goods.
“We know that this species is often found mixed in with shipments of agricultural products,” said Rafe Brown, curator of herpetology and leader of the team that published the recent scientific article. “It is reasonable to assume that humans, in the daily commerce of food products around the country, have contributed to the spread of the Asian tree frog throughout the Philippines.”
Meanwhile, scientists are baffled by the presence of the Asian tree frogs on nearly every island in the Philippines that has been surveyed by biologists. The species’ recent arrival on many hundreds of islands defies a natural explanation and suggests that humans must have been involved in the spread of its populations. Brown also cited a recent study by Japanese biologists who concluded that humans had brought Philippine Banana Frogs to the as far north as the rice fields of Japan.
“These findings suggest that Filipinos, in our every day comings and goings, have contributed to the expansion of Banana Frog populations throughout the country,” said T. Mundita Lim, Director of PAWB-DENR. “The results of this study reinforce the idea that humans may have a real impact on the distribution of animal life in the Philippines.”
On a more serious note, Lim emphasized that the new study by Brown and colleagues demonstrated how quickly an invasive species can spread if humans are not careful and take steps to prevent exotic species introductions. Lim cited the case of the American Cane Toad, which was introduced into the expansive sugar cane plantations on Negros a century ago in hopes that it would control insect pest species, only to become a major pest itself.