Last updated on April 17, 2014 at 7:54 EDT
Vibrational Cues for Embryos Image 3
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Vibrational Cues for Embryos (Image 3)

July 20, 2010
Three-day-old embryos of red-eyed treefrog species Agalychnis callidryas, taken in Gamboa, Panama. Although these embryos are not developed enough to hatch, they have well-developed external gills, which they position in the best oxygenated part of the egg--near the all-exposed surface. This allows them to maintain a high metabolic rate and rapid development, despite very low oxygen levels deeper inside their egg. This image was taken as part of a research project examining how hatching timing is cued by risks. (Date of Image: 2005) [Image 3 of 5 related images. See Image 4.] More about this Image The research is being conducted by Karen Warkentin of Boston University, and focuses on the mechanisms, evolution and ecological consequences of adaptive plasticity in life history switch points, particularly hatching. Warkentin is examining how the timing of hatching is cued by risks in A. callidryas. She is also studying related species--including some whose embryos respond differently to risk--in order to better understand how elements that contribute to hatching plasticity have evolved and the cumulative effects of plasticity across egg, larval and metamorph stages, to learn how fear and death combine to affect natural selection and population ecology. Warkentin's overall research program on adaptive plasticity of hatching in red-eyed treefrogs has been supported by the National Science Foundation (NSF) at several stages, including a dissertation improvement grant, when she first discovered the plasticity, and two grants for her research as faculty at Boston University. She also received a grant from NSF's Division of Integrative Biology and Neuroscience (IBN 02-34439) that focused on the mechanisms of hatching plasticity, specifically on how embryos use vibrations to assess predation risk; and a grant from NSF's Division of Environmental Biology (DEB 07-16923), that addressed the ecological importance of plasticity across egg, tadpole and juvenile states.