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Tarantulas are capable of spinning different types and amounts of webbing for different tasks. However, generally speaking, they only lay 'sticky' webbing when they actually need to anchor it to the ground, rather than true spiders, who use sticky webbing extensively to catch prey. Likewise, tarantulas do not try and hang off a single strand of webbing like some true spiders, most likely because they are simply too big and heavy for it to support them.
here is the link, go read some more
www.thespiderdiaries.co.uk/content/view/201/30/