How ticks get under your skin

A new look at a tick’s mouthparts shows how the arachnid saws its way through skin and hangs on for up to a week. The castor bean tick Ixodes ricinus, a European species that carries Lyme disease, faces an engineering problem: Its needlelike mouthparts are good at piercing but useless for hanging on during long periods of feeding. And unlike some ticks, this species does not make a cement to anchor itself to its host.

Using a scanning electron microscope and videos to magnify their subjects thousands of times, German and U.S. researchers found that the ticks use a two-step process to ratchet their way in. First a pair of chelicerae (the winglike structures at top) telescope out to pierce the skin, pumping alternately like engine pistons to gain a foothold. Then the chelicerae switch to a breaststroke motion that draws in the barbed tonguelike needle, or hypostome (center). The tick’s method may inspire engineers to mimic it, the