this week in science.doc

this week in science Size Matters CREDIT: FRED NIJHOUT/DUKE UNIVERSITY Animals regulate their growth so that all organs are mutually proportional, even when growth occurs at different times. However, the mechanism by which this occurs is unknown. Nijhout and Grunert (p. 1693, published online 25 November) performed an analysis of relative wing growth in the tobacco hornworm, Manduca. Animals that were small owing to starvation had smaller wings, due to their slower growth rate, and they also stopped growing earlier than large, well-fed larvae. The insect hormone ecdysone was implicated in the process that governs this scaling relationship between adult wings and body size. -------------------------------------------------------------------------------- Unlikely Planet Most known extrasolar planets orbit stars similar to the Sun. Very few planets have been detected around metal-poor stars whose abundances of elements other than hydrogen and helium are much lower than those of the Sun, or around stars that are at a late stage in their evolution. Setiawan et al. (p. 1642, published online 18 November)