The diversity and abundance of parasites associated with Xenopus laevis (Daudin, 1803) in selected habitats

[摘要] English: The African clawed frog, Xenopus laevis, has been extensively utilised over the yearsfor a variety of research projects. The frog proved particularly useful as parasite studymaterial because of its diverse parasite assemblage. The parasites of Xenopus representseven major invertebrate groups, and no less than 29 parasite species are foundassociated with X laevis utilising all organs except the lungs. The rich diversity ofXenopus parasites is related to the fact that the frog is primarily water living, whichfacilitates parasite transfer.Despite the extensive research that has been done on the parasites of Xenopus, thereis little information available on parasite ecology from field based studies. It is known,however, that parasite infection levels are determined by interaction of ecological factorsand parasite and host characteristics. Due to the lack of information in this respect, afield based study was undertaken to determine what impact variations in climate,ecology, host size or age, and host sex have on the diversity and infection levels ofparasites of X laevis.Two ecologically different localities were chosen for the purpose of the study. Usingbaited traps, X laevis were collected during different months over a two year period, andthe infection levels of the different parasites determined. The infection levels of parasitesin hosts of different size and sex were also determined.All the parasites found in the study occurred at both localities, but infection levelssometimes differed significantly. Although the infection levels varied through the time ofthe study, the seasonal patterns were not always clearly defined. Definite positive or negative correlation between size and infection levels was found for most of theparasites. The relationship between host sex and infection levels was, however,inconclusive.AJthough the parasites of Xenopus have been extensively studied, a new parasite wasfound in the bile ducts of the frog. The cyclophyllidean plerocercoid, Valiparacampylancristrota (Wedl, 1955) (Cestoda: Dilepididae), was originally recorded fromthe gall bladder of the tench, Tinea tinea. The morphology and life cycle of the parasitewas investigated. A juvenile leech found on the external surface of X. laevis. waspreliminarily identified as Marsupiobdella africana, a leech known to infect Xenopus.

[发布机构] University of the Free State