Showing papers by "Jonathan B. Losos published in 1993"

Trade-Offs Between Sprinting and Clinging Ability in Kenyan Chameleons

Abstract: We measured the force required to pull chameleons from perches of varying diameters and the sprint speed of chameleons on flat surfaces and on perches of varying diameters. The two species examined differ in their degree of terrestriality: Chamaeleo jacksonii is almost completely arboreal, whereas C. dilepis is semi-arboreal and is often observed on the ground. We tested the following hypotheses: (a) each species has relatively greater sprinting and clinging abilities on surfaces corresponding to those it uses most frequently; or (b) a trade-off exists between maximizing clinging and sprinting abilities. The results support the second hypothesis: C. dilepis runs faster than C. jacksonii on almost all diameters, but has poorer clinging ability on all diameters

Habitat use and ecological interactions of an introduced and a native species of Anolis lizard on Grand Cayman, with a review of the outcomes of anole introductions

Abstract: Since its introduction ten years ago, Anolis sagrei has spread over much of Grand Cayman and is now more common in some habitats than the native anole, A. conspersus. Interspecific differences in body size, perch height, and microclimatic preference may have facilitated the colonization. Nonetheless, competition may be occurring between the species; comparisons with studies of habitat use prior to the arrival of A. sagrei indicate that in open habitats, where A. sagrei is now abundant, A. conspersus perches higher, but in closed habitats, where A. sagrei is absent, no change in perch height is evident. Review of data concerning 23 Anolis introductions indicates that the presence or absence of an ecologically similar native species may be an important determinant of colonization success or failure.