By Stephen Beech Day-old caterpillars one-twentieth the size of a grain of rice can recognize the footsteps of predatory ladybugs, reveals new research. Warty birch caterpillars, less than 1.5 millimeters (0.06 inches) long, defend their leaf tip homes from invading caterpillars by scraping and pounding the leaf to warn off potential invaders. But scientists were […]