Yes, there is. Silk can occasionally drop from enemies, but not in sustainable quantities. Another option is extracting Silk from Fat Grubs. This requires you to place a Tier 4 named Tanner thrall onto your Artisan table, and supply him with Fat Grubs, which can be difficult to find in large quantities. From there, your Tanner thrall will do something that probably borders on animal cruelty, and he'll manage to extract some Silk! This isn't a very sustainable method though, so traditional farming is preferable if you require a large quantity.