A Comparison of the Foraging Biology of Two Tropical Gecko Species in Disturbed Areas

Abstract. The traditional foraging mode dichotomy in lizards has been one of ambush predators vs. wide ranging predators. Each mode has been associated with its own suite of other complementary characteristics, including metabolic rates, sensory capacities, as well as predator and prey species. While foraging mode within lizard families is often consistent, few studies have compared the foraging modes of sympatric members of a clade in which one species is nocturnal and the other diurnal. Hemidactylus frenatus, an introduced, nocturnal house gecko, and Gonatodes albogularis, a native, diurnal species, inhabit disturbed habitats in Costa Rica. Using traditional movement-based indices, moves per minute (MPM) and percent time spent moving (PTM), we found H. frenatus to move significantly less (MPM = 0.47) and spend significantly less time moving (PTM = 0.74%) than G. albogularis (MPM = 0.97, PTM = 3.94%) during peak activity times. One reason for this difference in activity level could be the beneficial effects of artificial lighting in attracting arthropods to H. frenatus foraging areas.