Few body parts have been put to such a variety of uses as have the palps of spiders.
More formally known as the pedipalps, these large, paired mouthparts are used variously to manipulate food, as supplementary walking legs, communication devices, sensory structures and sex organs.
In some species – especially the tarantulas and their kin – they are so limb-like that their owner can look like it has ten legs rather than the customary eight.
In jumping spiders, they are often brightly coloured and flashed semaphore-style at rivals and potential mates. Some wolf spiders use them as drumsticks, to tap out rhythmic signals on the ground.
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In sexually mature male spiders, the palps terminate in bulbous tips resembling boxing gloves (a handy rule of thumb for distinguishing males and females).
These are used to suck sperm from the genital opening on a male’s belly and inject it into the female’s reproductive tract during mating.
A close look at the bulbs with a hand lens reveals them to be complex structures adorned with various nozzles, flanges, bristles and folds.
Their precise shape varies dramatically between species – even very closely-related ones – so they are essential identification tools in spider taxonomy.
Main image: A spider's palps or pedipalps are paired mouthparts. © Heather Broccard-Bell/Getty