It may be smaller than a grain of rice, but the aptly-named porcupine-Velcro millipede Polyxenus fasciculatus is one tough cookie. <\/p>\n
When assaulted, often by an ant<\/a> or spider, it turns tail but doesn’t run. Its rear end is equipped with two tufts of microscopic bristles, each shaped like a grappling hook.<\/p>\n As the millipede pivots, it splays these weapons and swipes them against its assailant. Many of the bristles snag on the hair-like setae on the insect’s face and front legs, and are pulled free of the millipede as it flees.<\/p>\n These weapons then do the rest. The shaft of each bristle is covered in hook-like barbs that further entangle the attacker as it tries to brush them off.<\/p>\n The loose bristles interlock in a similar fashion to Velcro, acting like a self-assembling net. After a few moments of struggle, the aggressor finds itself hog-tied and left to die.<\/p>\n The millipede never runs out of ammo. It has enough bristles for multiple attacks, and its full arsenal is renewed at every moult – in fact, using them may spark moulting.<\/p>\n The tactic almost never fails in this North American species.<\/p>\n But closely related millipedes in Brazil and Central America that use this same defence have met their match.<\/p>\n Thaumatomyrmex ants have evolved long, smooth, pitchfork-like mandibles, which they use to trap and hold their prey at a distance. The captive’s tufts, too short to touch the ant’s face, are rendered useless. The predator then kills with a sting of venom<\/a>, carefully strips its ‘coat of arms’ and enjoys the meal. <\/p>\n