Meeting Abstract

22.12  Wednesday, Jan. 4  Horizontal and vertical landing in the Cuban tree frog, Osteopilus septentrionalis HICKS, R.; MACESIC, L.J.; GILLIS, G.B.*; Mount Holyoke College; Mount Holyoke College; Mount Holyoke College

Recent work focused on what happens after takeoff in frogs and toads is revealing that Anurans approach landing in different ways. Specifically, the use and movements of both the forelimbs and hindlimbs differ radically between species that land with varying degrees of coordination. Tree frogs are known for inhabiting a complex arboreal environment and because of their toe pads are capable of landing on diverse surfaces that can be at just about any orientation (consider the leaves and branches on which we often see tree frogs photographed). The goal of this study was to determine whether Cuban tree frogs, Osteopilus septentrionalis, prepare for landing differently depending on the orientation of the substrate. High-speed video recordings indicate that, indeed, the patterns of movement of the forelimbs and hindlimbs during horizontal hops differ from those in which the animal leaps to a vertical surface. When performing horizontal hops, the tree frog rapidly moves its forelimbs after takeoff to be in a position to absorb the impact of landing while the hindlimbs are rapidly folded back into a flexed position. In contrast, after takeoff toward a vertical surface, the hindlimbs remain extended until impact and the forelimbs are rarely the first part of the animal’s body to make contact. Instead, it is generally the head or trunk that first makes contact with a vertical surface, after which the forelimbs are quickly moved to a position that allows the toepads to adhere, and the legs are pulled in. Our preliminary data suggest that when approaching a landing surface this species varies its limb movements depending on the orientation of that surface.