Tiny barbs, sharper than any fish hook, cover the shafts of the bristles. At each bristle end is a three-pronged hook to clench the body hairs of other insects. Maria Eisner's SEM images show the perplexed ants, immobilized by an interlocking mesh of millipede bristles. And if P. fasciculatus are anything like a closely related millipede species, P. lagurus, their bristles are renewable when they molt. The bristle-baring millipedes are not the only arthropods with a mechanical advantage, the biologists observe in their PNAS article.
Tarantulas use their legs to flick the loose hairs on their backs toward predators.
And some caterpillars are protected by stinging hairs, which they also use to impregnate their cocoons when they pupate. But there is one Brazilian ant in the Thaumatomyrmex genus that was known to cope with bristle millipedes by grabbing them with its specialized mandibles, killing the prey with a sting, stripping them of their bristles, before finally eating the millipedes. For every strategy, no matter how 'perfect,' there is a counter-strategy.