Ambush and active foraging modes both occur in the scincid genus Mabuya

Foraging methods of insectivorous lizards fall into two major modes, ambush foraging, in which the lizard waits immobile to detect prey, and active foraging, in which the lizard moves through its habitat while searching for prey. Both modes exhibit remarkable phylogenetic stability. Ambush foraging is the sole mode of all iguanians examined to date, and active foraging is the only known mode in large scleroglossan clades such as Teiidae and Varanoidea. We present quantitative data on foraging behavior demonstrating the existence of intrageneric variation in foraging mode in the scincid genus Mabuya in southern Africa. Like the large majority of skinks, Mabuya striata sparsa, M. sulcata, and M. variegata are active foragers that have high values of number of movements per minute (MPM), proportion of time spent moving (PTM), and mean speed (average speed including time spent immobile) but relatively low speed while moving. In contrast, M. acutilabris and M. spilogaster are ambush foragers having significantly lower MPM, PTM, and mean speed but higher average speed while moving than the other species. The importance of these findings is twofold. First, intrafamilial variation in foraging mode in Scincidae and intrageneric variation are verified for Mabuya. Second, because intrageneric variation in foraging mode was previously known from quantitative data only in the lacertid genera Acanthodactylus and Pedioplanis (and atypically in Meroles), an excellent opportunity is provided to test hypotheses about foraging mode without confounding interfamilial phylogenetic differences.