A Comparative Analysis of the Diets of Pelusios Turtles across Africa †

Pelusios is an Afrotropical endemic genus of freshwater turtles that have adapted to a variety of habitats, with savannahs and forests being their two main habitat types. Although considered generally carnivorous, these turtles have rarely been subjected to detailed field surveys for determining their quantitative diet. In this paper, by using both literature and original data, we analyse the diet of several Pelusios populations: three P. adansonii populations from South Sudan, one P. nanus from Zambia, seven P. castaneus from Nigeria, Benin and Togo, and four P. niger from Nigeria. All species were omnivorous but with a clear preponderance of the prey items being of animal origin (amphibians, fish, arthropods and anellids). Saturation curves revealed that the diet composition of all the surveyed populations was adequately assessed, and the diversity profiles indicated that all the populations were relatively similar in terms of overall dietary diversity. General Linear Models (GLM) showed a negative effect of vegetation cover on Anura adults consumption by turtles, while showed that the frequencies of Anura tadpoles, fish, reptiles and birds on Pelusios diets increased with the increase of vegetation cover. The GLM model also showed positive effects of individual body size on algae, Bivalvia, reptiles, birds and small mammals consumption by turtles, while underlined that the predation on Arachnida decreased with the increased of turtles body size. All species appeared substantially generalist in terms of their diet composition, although the effects of season (wet versus dry) were not adequately assessed by our study.