AsianScientist (Aug. 3, 2016) – Researchers conducting a field study in Japan have found Japanese tadpoles living in hot springs, or onsens, withstanding the hottest ever recorded temperatures for any amphibian tadpole.
The study, published in the journal Amphibia-Reptilia, was carried out by scientists at Hiroshima University with collaborators at the Graduate University for Advanced Studies (SOKENDAI).
The Japanese stream tree frog, known to scientists as Buergeria japonica, is widely distributed across the southern islands of Japan and Taiwan. While the species is known to inhabit hot springs, this phenomenon has only been observed in Taiwan.
In this study, the researchers focused on tadpoles from a hot spring on Kuchinoshima Island, a tiny volcanic island of southwestern Japan. They discovered that the tadpoles were able to live and grow in water temperatures as high as 46.1 °C. Living in an onsen may benefit the tadpoles’ immune systems, speed their growth, and allow the tadpoles to survive on small volcanic islands where there are few other natural sources of fresh water, the researchers said. By adapting to survive in water too warm for other amphibians, it may have allowed the frogs to exploit new habitats and avoid competition from other species.
“Scientists have studied the distributions of organisms and their environmental adaptations since the era of Darwin and Wallace,” said Assistant Professor Takeshi Igawa from Hiroshima University, the corresponding author of the current study.
“Our report is one of the best examples of a direct connection between an animal’s physical ability to tolerate diverse environmental conditions and the animal’s success at colonizing diverse geographic areas.”
The researchers did not find any adult frogs in the onsen, which suggests that the species may only be adapted to high temperatures during the tadpole stage of life. Future research will focus on the details of the tadpoles’ behavior in their habitat, they said.
The article can be found at: Komaki et al. (2016) Living in a Japanese onsen: Field Observations and Physiological Measurements of Hot Spring Amphibian Tadpoles, Buergeria japonica.
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Source: Hiroshima University; Photo: Nicki Dugan Pogue/Flickr/CC.
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