Diet of Five Trachylepis Skink Species (Scincidae: Mabuyinae) in Savanna Biome of Namibia

Abstract

Lizards, especially skinks (Scincidae) occurring in arid environments constitute good study objects to test niche differentiation and other related issues of interspecific competition. Diet of five Trachylepis skink (T. punctulata, T. binotata, T. capensis, T. wahlbergii, T. damarana) was studied through stomach content analysis. Skinks were collected in savanna habitats in Namibia. In all these species, active foraging strategy predominates. All skink species preyed almost exclusively on insects. Four insect taxa comprised the bulk of diet in all five species investigated: Coleoptera, Orthoptera, Isoptera, Hymenoptera (Formicidae) and larvae. Their overall contribution ranged from 72.2% to 100.0% of all prey items in the diet of particular skink species. Most prey items were below 10 mm long, some were 11-20 mm in length. Both males and females fed on the same prey groups, but there were marked differences in the proportions of these groups. In general, males preyed more on beetles and grasshoppers, while females – more on ants. All main prey groups were recorded both in dry and in wet season in all five skink species. Food niche overlap was the highest between T. damarana and T. wahlbergii (0.84), and between T. binotata and T. punctulata (0.77). No overlap in food niche was recorded between T. capensis and T. punctulata, and low overlap (0.26) between T. capensis and T. binotata.