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Invasive frog claims another continent

A new population of African clawed frogs (Xenopus laevis) has become established on mainland China, according to a new publication by C·I·B Core Team Member, John Measey. Working with colleagues from the Chinese Academy of Sciences, Measey trapped a site near the city of Kunming, Yunnan Province. The African clawed frogs they found were all albinos, the most common form in the pet trade. Previous work by Measey had shown that the vast majority of African clawed frogs moving around the world in the pet trade originate from China.

Invasive populations of African clawed frogs are known from Europe, North and South America and were previously only known from Japan in Asia. This discovery now places an invasive population on continental Asia with the potential for a much larger invasion in this area. These frogs are known to heavily impact local amphibian and invertebrate populations.

Traps out in the evening at the side of the aquaculture area

Traps out in the evening at the side of the aquaculture area. These simple bucket traps are baited with chicken livers to attract the African clawed frogs. (Photo credit: John Measey)

Trade in the African clawed frog started in the 1930s following their use as the first pregnancy test. The species was so easy to keep that it then became the standard laboratory amphibian all over the world, a status it continues to enjoy today. Breeding in laboratories has become so successful that animals are no longer exported from South Africa. Since the 1980s, however, this species has become very popular in the pet trade. Now hundreds of thousands of animals are shipped around the globe destined to become aquarium pets.

The researchers used molecular methods to check whether members of the invasive population carried the fungal chytrid pathogen, known for decimating amphibian populations globally. All frogs caught tested negative. However, the site is known for having a population of American bull frogs, which the team heard calling as they set out the traps. It is unknown how these two globally invasive frogs interact.

“The site is on the edge of Lake Kunming, possibly allowing these frogs access to a large area in southern China”, said Measey. “We were surprised to find an established population as this area fell outside the global climate model predicting suitable areas.”




Read the paper

Wang, S., Hong, Y. and Measey, J. 2019. An established population of African clawed frogs, Xenopus laevis (Daudin, 1802), in mainland China. BioInvasions Records (2019) Volume 8, Issue 2: 457-464. DOI 10.3391/bir.2019.8.2.29.

For more information, contact John Measey at jmeasey@sun.ac.za