Taking up Tony's challenge... If you do want a more "technical" term, this, I think, is it. Actually "hairs" is perfectly OK, and many bee-related texts use it. They are specifically the "hairs" on the bee's legs which it uses as "combs" and "brushes". Here's a nice page on bees' legs:
http://www.bumblebee.org/bodyLegs.htm#combs and brushes

"Le premier segment des trois paires de pattes possède une touffe de soies à sa face interne [...]"
https://books.google.es/books?id=_VvsNzmvkp4C&pg=PA532&lpg=P...

"Seta, plural: setae, is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms."
https://en.wikipedia.org/wiki/Seta

"The term scopa (Latin: a broom) is used to refer to any of a number of different modifications on the body of a non-parasitic bee that form a pollen-carrying apparatus. In most bees, the scopa is simply a particularly dense mass of elongated, often branched, hairs (or setae) on the hind leg."
https://en.wikipedia.org/wiki/Scopa_(biology)

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Note added at 21 mins (2015-08-16 18:24:22 GMT)
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Sorry, your question is "soie", singular, and the singular of setae is seta, so that should really have been my answer.