Insights from foraging behavior on competitive interactions in introduced lizards in Hawai‘i

Abstract

Foraging behaviors have different affects on multiple aspects of an animal’s ecology. Thefitness of an animal depends heavily on the body condition of said animal, and foraging has a direct affect on body condition. Foraging behaviors also dictate the types of prey predatory animals hunt, and where they hunt for this prey, both of which can drive competition for food. Exploitation competition could be a mechanism of competition being driven by foraging behaviors. Using focal animal sampling, we compared different aspects of foraging behavior on three species of invasive diurnal lizards in Hawai’i that may be competing for food: Anolis sagrei, Anolis carolinensis, and Phelsuma laticauda. Lizards were housed in single-species populations in experimental enclosures with similar prey and habitat availability. We observed differences in the heights at which Anolis sagrei and Phelsuma laticauda would forage, and Anolis carolinensis overlapped with both species. Anolis sagrei and Anolis carolinensis used the ground to forage, whereas Phelsuma laticauda was rarely seen using the ground to forage and used smooth substrates more than the other two species. Both Anolis species had similar long distances traveled to a prey item, whereas Phelsuma laticauda rarely traveled long distances to attempt to capture prey. There was overlap between all three species in the prey taxa they would hunt, which is supported by other work done on Anolis. Because of overlap in foraging behavior seen among the species, exploitation competition could be occurring and help explain why Anolis carolinensis has declined in abundance on O’ahu since the introduction of the other two species.