Evidence of predation on the Helmeted water toad Calyptocephalella gayi (Duméril & Bibron, 1841) by the invasive African clawed frog Xenopus laevis (Daudin 1802) (original) (raw)
The ongoing invasion of African clawed frogs ( Xenopus laevis ) in Chile: causes of concern
Biodiversity and Conservation, 2005
We review the existing data on the African clawed frog in Chile (Xenopus laevis, Pipidae) and report new and alarming information on its distribution, provide physical data on water courses and bodies that hold populations of this frog, report observations on its diet, on mass migration overland, and on predation by native birds. Our findings reveal that: (a) the spread of the invasion is currently covering 4 of the 13 regions of Chile; (b) clawed frogs are found at higher densities in artificial water bodies (ponds and dams and irrigation canals) rather than in natural lagoons or streams or rivers; (c) there is no evidence of predation on native anurans, but rather on their own larvae; (d) they face predation from native birds. Causes of concern include (a) that African clawed frogs in Chile reach both lower and higher altitudes than formerly estimated, and (b) that they are able to migrate overland to colonize other water bodies. They are spreading at a rate of 3.1-3.9 km=year in an optimistic scenario, and at a rate of 4.4-5.4 km=year in a pessimistic one. The most troubling aspects of the African clawed frog invasion in Chile involve: (a) their unaided spread through central Chilean agricultural areas, using irrigation canals and overland migration; and (b) the type of interactions that they may be establishing with native anurans (are they competitors, predators, habitat modifiers, disease vectors, or all things together?). As a precautionary action, we propose that the pet trade of African clawed frogs in Chile should be banned.
Ongoing invasions of the African clawed frog, Xenopus laevis: a global review
Biological Invasions, 2012
We conducted a literature review on the current status of all known extralimital populations of the African clawed frog, Xenopus laevis, to identify commonality in invasion pathways, lag between discovery and introduction, and whether old populations are in decline. Further, we investigated which locations are vulnerable to future establishment using geospatial data (1,075 native and 124 invasive records) in a Maxent model developed with data from the Worldclim database. We found introductions of X. laevis to be continuous over the last 50 years and invasions to be ongoing on four continents: Asia, Europe, North and South America. Invasion pathways were related to scientific use and the pet trade, with high rates of deliberate release followed by a lag of 2-25 years to first reports. No populations were found to be declining although some have been extirpated. Optimal uninvaded bioclimatic space was identified in Electronic supplementary material The online version of this article (
African Journal of Ecology, 2018
Predators are not limited to prey from other species as they can cannibalise vulnerable individuals within their own population. The African clawed frog, Xenopus laevis (Daudin), is a predator with a broad diet, known to consume multiple prey species, including congeners and conspecifics. African clawed frogs occur in sympatry with the Endangered Cape platanna, Xenopus gilli Rose & Hewitt, which are under threat through competition and predation from X. laevis. We investigated the threat of X. laevis predation on X. gilli using choice and no-choice experiments to evaluate the relative vulnerability of X. laevis and X. gilli larvae. Results showed that large X. gilli larvae had a significantly higher vulnerability to X. laevis predation compared to small X. gilli larvae. However, the same discrimination was not discerned when offered large and small X. laevis larvae, or mixed larvae of the same size. We report ontogenic shifts in behaviour of X. gilli larvae that may be a factor in contributing to the vulnerability of large X. gilli larvae to adult X. leavis predation. Congeneric predation likely has negative implications for the population structure of the Endangered X. gilli. Our study underlines the call for the removal of X. laevis to conserve populations of X. gilli. Résumé Les prédateurs ne se limitent pas aux proies d'autres espèces car ils peuvent cannibaliser les individus plus vulnérables de leur propre population. Le xénope lisse Xenopus
Aquatic Invasions
When species are translocated to a novel environment, individuals become exposed to new predators against which they may not express very efficient defences at least at an initial stage. The strength of anti-predator defence is an important parameter that may determine the ability of local communities to control the expansion of invasive populations. The African clawed frog, Xenopus laevis, is a globally invasive amphibian that has successfully established invasive populations on four continents. In its invasive distribution in western France, X. laevis encounters novel aquatic predators. Some may be related to the predators in the native range but others may belong to different taxonomic groups and not be functionally or ecologically equivalent. We tested whether naïve X. laevis tadpoles from the invasive French population exhibit anti-predator response to local predators, and whether the response depends on the degree of relatedness with predators encountered in the native range of the frog, or whether individuals may express generic neophobia to any cue they are not familiar with. We exposed naïve lab-reared tadpoles to a native non-predatory water snail, Planorbarius corneus, a native predatory beetle, Dytiscus dimidiatus, and an invasive predatory crayfish, Procambarus clarkii. We found that X. laevis tadpoles innately reduce their activity when exposed to beetle and crayfish stimulus cues, but not to snails. Reducing activity can decrease the probability of being detected by predators. This demonstrates that invasive tadpoles respond to known and novel predators regardless of the evolutionary history. Whether the produced response is always effective against a totally novel predator remains to be tested.
First parasitological study of the African clawed frog (Xenopus laevis, Amphibia) in Chile
Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
Introduced species can arrive into new territories with parasites; however, these species are expected to face lower parasite richness than in their original regions. Both introduced hosts and parasites can affect native fauna. Since their release into the wild in Chile following laboratory use, Xenopus laevis Daudin, 1802 has widely spread throughout central Chile. The only pathogen described on the host is the fungus Batrachochytrium dendrobatidis Longcore, Pessier, Nichols, 1999; thus, this is the first parasitological study of this species in Chile. In 10 localities in central Chile, 179 specimens of X. laevis were captured and examined for parasites in the gastrointestinal tube, cavities, lungs, liver, and skin. Only nine specimens of the genus Contracaecum Railliet, Henry, 1912 were found in six specimens of X. laevis from a private dam in La Patagua. It is likely that these parasites originated from species of native birds. This is the first record of Contracaecum sp. in Chil...
Rana catesbeiana (American Bullfrog) is exotic in western North America and is sympatric with two native species, Rana luteiventris (Columbia Spotted Frog) and Pseudacris regilla (Pacific Treefrog). In a laboratory experiment, we assessed the growth of tadpoles of R. luteiventris and P. regilla in the presence and absence of tadpoles of R. catesbeiana. We found that in the presence of tadpoles of R. catesbeiana, P. regilla exhibited rapid growth in early larval stages compared to R. luteiventris. A second experiment indicated that, when reared with R. catesbeiana, P. regilla increased activity levels; this behavioral disparity may partly explain the observed difference in growth responses of the two frog species to R. catesbeiana competition. Our results suggest that tadpoles of P. regilla display greater growth and behavioral plasticity than do R. luteiventris, when subject to competition with R. catesbeiana. Rana luteiventris may be more susceptible than P. regilla to R. catesbeiana-mediated numerical decline, if exploitative or interference competition between tadpoles is a population-limiting factor in western breeding ponds.
The Southwestern Naturalist, 2014
The African clawed frog (Xenopus laevis) is an invasive amphibian in at least 15 countries. In Mexico, only occasional records have documented it in the state of Baja California. In May 2013, we discovered a population at Puente el Morro in Rosarito. In a 1-h session of trapping, we captured 106 individuals (adults and juveniles) at a small pond. We did not see eggs, tadpoles, or reproductive activity, but lengths of frogs indicate that some have reached sexual maturity. This discovery indicates the need for conservation plans and action against X. laevis dispersion, especially in Mediterranean zone climates.