A butterfly's secret to long life  January 2013

Why humans don't gallop  January 2013

January 2013  
A butterfly's secret to long life
by Cameron Walker

Credit: Pave Väisänen

Live fast, die young. That seems to be the mantra of the animal kingdom. The more energy a creature burns, the more free radicals and other unstable, cell-damaging molecules its body produces—and in some cases, too many of these can shorten lifespans. But the Glanville fritillary butterfly (Melitaea cinxia) doesn't seem to have gotten the memo. When researchers measured the metabolic rates of this intricately patterned insect, they found that butterflies that expended the most energy during flight also lived the longest, whether they were lab-bound or released to island meadows in Finland. The findings suggest that the connection between oxidative stress—the long-term buildup of free radicals and similar detrimental molecules—and lifespan may be more complicated than previously thought. The ability to fly in top gear might indicate that a butterfly is naturally in better shape—whether through access to more-nutritious food or individual genetics—to override high metabolism's harmful side effects, the researchers reported online last month in The Journal of Experimental Biology. But they also wonder whether butterflies adapted to high-powered flight might have evolved ways to protect themselves from their own high-speed metabolisms.