Diet of feral Xenopus laevis (Daudin) in South Wales, UK

African clawed frogs (Xenopus laevis) in a South Wales pond ate a wide vari ety and size range of prey. Zoobenthos and zooplankton made the greatest co ntribution to diets, both numerically and by weight. Terrestrial invertebra tes made up a small proportion of the diet numerically but a large proporti on of the diet mass during the spring and summer. Nektonic prey were presen t throughout the year but made up a very small proportion of diet. Cannibal ism was important when eggs and larvae were present in the pond. Electivity values were consistently positive for chironomids (larvae and pupae) and d aphnids but were consistently negative for tubificids. In addition, electiv ity increased for larger sizes and pupae of Chironomus plumosus, but was lo w for the largest size class (> 12 mm). Electivity of other taxa showed an increase when densities of chironomids and daphnids were reduced. Mean size s of daphnids and cyclopods were consistently larger in frog stomach conten ts than in the water column, indicating that predation on zooplankton by Xe nopus laevis is size-selective.