Sd. Marshall et al., SETAL ENTANGLEMENT - AN UNDESCRIBED METHOD OF STRIDULATION BY A NEOTROPICAL TARANTULA (ARANEAE, THERAPHOSIDAE), Journal of zoology, 235, 1995, pp. 587-595
The theraphosid spider Theraphosa leblondi (Latreille) produces a sibi
lant, hissing sound during defensive displays. This sound is produced
using a previously undescribed method of stridulation: setal entanglem
ent. The opposing surfaces of the femora of the pedipalps, first, and
second pair of legs are clothed in unique setae which have their dista
l portion bearing hooks and a shaft clothed in filaments. Experimental
ablations described here showed these plumose setae to be the site of
sound production. Based on examination of the fine structure of these
setae, we propose that the hissing sound is produced by the entanglem
ent and pulling apart of the hooks at the ends of the setae on one leg
surface and the long, plumose filaments on the median part of the set
ae on the opposing leg surface. Evidence presented suggests that this
is a case of an acoustic aposematic display directed at vertebrate pre
dators.