Life

One type of squid camouflages itself with reflective eyes, plus more in this week's news

Squid eyes
Like a poker player sporting aviator sunglasses, a species of squid has developed a clever way to camouflage its eyes from potential predators. In the deep ocean, the light coming from behind an approaching predator is identical to that coming from behind its prey — so an animal that can reflect this light will appear invisible. Published online February 16 in the Journal of the Royal Society Interface, research from the University of California, Santa Barbara, reveals how the silver lining over the squid’s eyes functions as a distributed Bragg reflector, a layered mirror that can match the underwater light and make the retina seem transparent. —Devin Powell

Sensitive plants pick the risks
Plants are smart enough, in their own green way, to make tradeoffs about accepting risk, researchers in Canada report. Animals typically tolerate more risk when food grows scarce. The sensitive plant (Mimosa pudica), famous for folding its leaves when touched, does the same thing, report Evelyn Jensen of the University of Alberta in Canada and colleagues. Folded leaves are less obvious to predators. And in dim light — the equivalent of scarce food for a photosynthetic plant — folded leaves take more risks by coming unfolded and out of hiding sooner than they do in bright light, the researchers say in the March American Naturalist. —Susan Milius

Guts in knots
WASHINGTON — The ancient Romans, who thought the future could be read in the complicated shapes of animal entrails, had it all wrong. These twists and kinks aren’t nearly so complicated, according to L. Mahadevan of Harvard University, who can reproduce them with a simple rubber tube stretched and then stitched to a sheet of latex. Unconvinced by a theory that blamed the cramped conditions of the abdominal cavity for these loops, which come in regular repeating intervals, he tested the idea that a digestive tube growing faster than the tissue connecting it to the body could create a twisting force. “When the rubber relaxes, we see a periodic structure of loops that arises spontaneously,” Mahadevan said February 18 at a meeting of the American Association for the Advancement of Science. — Devin Powell