There are at least five different respiratory systems in spiders, depending on taxonomic group
and whom you’re talking to.
1) A single pair of booklungs, as with the cellar or daddylongleg spiders, Pholcidae.
2) Two pair of booklungs, suborder Mesothelae, and all or most of infraorder Mygalomorphae
(including tarantulas).
3) A pair of booklungs and a pair of tubular trachea, as in the orbweavers and wolf spiders, and
probably most species of spiders.
4) A pair of tubular trachea and a pair of sieve trachea (or two pair of tubular trachea if you’re
one of those who doesn’t believe the difference between tubular and sieve trachea is enough to
distinguish them from each other), as in the small spider family, Caponiidae.
5) One pair of sieve trachea only (or tubular trachea to some), as in the small spider family
Symphytognathidae.
Did you mean in humans? Well you have to do your own homework. Either open your text book or google it yourself.
