MOVEMENTS OF SCOPULATE CLAW TUFTS AT THE TARSUS TIP OF A TARANTULA SPIDER

摘要

The scopulate claw tufts at the tip of the tarsus in the tarantula spider Grammostola cala spread out during locomotion to provide a greater area of contact for these hairs involved in gripping the substrate. This spreading action of the claw tufts is coupled to the depression of the tarsal claws and is brought about by the tufts inserting on the arthrodial membrane either side of the tarsus-claw articulation and spreading as this membrane is drawn forwards during claw depression. Hydrostatic haemolymph pressure may also play a part in spreading the tufts. The claws and claw tufts are coupled to act together to increase grip during locomotion on uneven surfaces. Tarsal scopulae may have a role in prey capture in theraphosids.