Friday, Oct. 24, 2014
60 ° Fair
Dr. Soraya Bartol|
|Course||BIO 375: Topics in Tropical Biology|
Once leatherback sea turtle hatchlings leave the nest, they are under intense predation pressure from terrestrial carnivores and must be able to find the sea rapidly. It is thought that hatchlings use multiple cues to find the sea post-emergence from the nest, but rely primarily on vision. We propose to test the role of visual cues on leatherback sea-finding behavior at Petite Tacarib, Trinidad, a known Leatherback turtle nesting site and a place where previous research courses to Trinidad have observed leatherback sea turtle nesting. Hatchlings will be collected as they emerge from the nest and placed in a holding container. We will immediately construct a 4m diameter circular arena on the beach in the same general location of the nest by digging a 30 cm deep by 15 cm wide trench. Thin boards will be used to divide the trench into 16 equal sized compartments. Hatchlings will be place in the center of the arena as a group (depending on the number taken from the nest) and will be monitored for 15 minutes. The observer will be seated far enough away from the arena so as to not interfere with movement, but close enough to prevent predation. At the end of 15 minutes, the number of turtles in each section of the trench will be counted. Multiple trials, consisting on various sensory cues, will be performed on each group of turtles. The first trial in the arena will always be the control trial (no additional sensory cues). Alternate sensory cues on subsequent trials may include artificial vegetation silhouettes place along different regions of the arena, including the seaward direction, artificial lighting, silhouettes and lights in combination, removal of all horizon visual stimuli, and removal of all visual stimulation. For the “blackout” experiments, the arena will be either partially or completely surrounded by black cloth attached to a PVC frame. In experiment 4, all light will be blocked (including moonlight) but the hatchling will still have the auditory stimulation of the ambient noise (i.e., crashing waves). Trials for each nest will be conducted in one evening, and hatchlings will be released prior to daybreak.
VFIC Competitive Fellowship for Undergraduate Research in the Sciences