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Egg-laying and Circadian Clocks

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On A Blog Around The Clock, Bora Zivkovic shares a newly published paper which he co-authored with researchers inspired by his blog. Their team recorded the egg-laying cycle of birds in the wild, where clutch sizes must answer to nature and not the hungry stewardship of a poultry farmer. They discovered that Eastern Bluebirds lay eggs along the same S-shaped interval curve observed in domesticated birds, which is “not dependent on external factors like food and energy, but [on] a fine-honed system of interactions between two circadian clocks.” On Not Exactly Rocket Science, Ed Yong enumerates the successful qualities of toads, which over a relatively short time “diversified into around 500 species and spread to every continent except Antarctica.” Although these pioneering amphibians may taste like chicken, some can lay clutches of 45,000 eggs at a time. On Neurophilosophy, Mo provides another example of circadian regulation, in the case of electric fish who must meter their power wisely. The discharge of some species, which can reach up to 500 volts, was found to be “weakest during the day, but its strength increased by approximately 40% at nighttime.” Fish use this electricity for perception as well as defense, and piscine social encounters also led to brief surges of power.

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