The Coevolution of Locomotor Morphology and Foraging Mode in Lacertid Lizards

Foraging mode is a behavioral syndrome used to relate a variety of morphological, behavioral, and physiological traits to prey acquisition behavior. Foraging mode is generally thought to be a continuum from ambush or sit-and-wait predation to a continuously searching or active form of predation. Ambush foragers feed on mobile prey items via short, rapid bursts of locomotion to capture passing prey. Alternatively, active foragers typically eat more sedentary or hidden prey that requires longer (or continuous) periods of movement to find and capture prey. Because locomotion patterns vary among foraging modes, morphology and performance of the locomotor apparatus (i.e. the hind limbs and pelvis) are intimately tied to foraging behavior. This relationship between ecology and morphology is adaptive and hence, should covary throughout the evolutionary history of a clade. Lizards in the genera Meroles and Pedioplanis (family Lacertidae) are a model system for investigations of foraging mode evolution because several species within these clades exhibit different foraging modes (ambush – active). Also, these taxa have diverged relatively recently compared to larger clades (e.g. Iguania, Scleroglossa) that are known to vary substantially in foraging mode. This study quantifies the locomotor morphology of Meroles and Pedioplanis species that have a range of foraging modes. Locomotor traits and foraging mode states are mapped on the phylogenetic relationships of the study species to test for the coevolution of morphology and behavior.