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.