9701222 Congdon Reptiles such as turtles lack behavioral parental care, such as birds feeding their young and mammals providing milk. In contrast, female turtles lay eggs in nests in the ground and subsequently return to their aquatic habitats. Nests are left unprotected and once hatchlings emerge from the nest they are on their own to find not only a suitable aquatic habitat but their own food as well. However, hatchling turtles do not leave the nests totally empty handed; they carry within their bodies some reserve yolk. Hatchlings may metabolize this yolk as fuel during their early life. The time that elapses before hatchlings feed can be surprisingly long. In some species of turtles, the hatchlings develop completely but then remain in the nest to overwinter. They may remain in the nest over 200 days before emerging in early spring. In other species, such as sea turtles, hatchlings emerge immediately after developing, race down the beach and then must swim out to seal until they reach offshore currents where they spend their first months of life. Sea turtle hatchlings may swim for several days without feeding. Evolutionary ecologists have hypothesized that providing the 'yolk' is one way females can increase the chances of their offspring surviving a critical period. Whether hatchlings with larger reserves perform better than hatchlings with smaller ones is unknown. The importance of the yolk reserves will be experimentally tested so that the ecological and evolutionary significance of varying amounts of yolk reserves can be better understood. Yolk reserves in hatchlings can be manipulated by removing a small amount of yolk. After the yolk reserves are reduced, the experimental animals can be compared to control animals in which the yolk reserves were not manipulated. Four questions will be addressed. How will reduced yolks affect the ability of the hatchling to overwinter in the nest? How will the reduced yolks affect the ability of the hatchlings to capture prey such a s small tadpoles? What will the growth and survival of the experimental animals be compared to the control group? And how will the ability to disperse overland to a home pond be affected? The last question will be answered by releasing hatchlings in areas used by nesting females. The shell and hind legs of the hatchlings will be coated with a color-coded dust that can be seen at night using a UV light. Each turtle will be followed to determine if it successfully reaches a pond. In combination these tests will demonstrate if and in what ways yolk sac reserves affect hatchling turtles.
