When you think of silk producing insects, spiders are likely the first that come to mind - and no wonder since I think most humans have gotten a distressing face-full of spider web at some point in their lives. And spider webs, when not gracing your face, are a marvel. I spent about an hour watching a spider maintain his web last time I was in Maine - I would place a blade grass onto the web, and the spider, fully aware that this was not a tasty treat, ambled over to the offending detritus, and carefully detached the strands of silk it was touching from the rest of the web. Incredible.
Or perhaps upon hearing of silk, you think of silk moths. Their silk fibers of their cocoons are woven into a textile we commonly know as...silk! Reading about how silk fabric is made might make you think twice about it - the larva of the silk moth (at this stage known as the silkworm) are farmed to cocoon stage. As the little silkworm inside prepares to transform into the beautiful silk moth, the cocoon is either dipped into boiling water or pierced through with a pin, killing the larva so that the cocoon can be unraveled as one thread (the strand of silk from just one cocoon can be over a mile long)! Emerging moths usually damage the cocoon - making the process of unraveling much more difficult. The untimely death of these little caterpillars, whose lives up to this point have been aiming solely towards the miracle of metamorphoses, just for a stupid article of clothing, well, it makes me a little sad.
Even some ants, bees and wasps produce silk for various uses.
Honeybee larvae produce silk to reinforce the wax cells in which they pupate, bulldog ant larvae spin solitary cocoons for protection during pupation, bumblebee larvae spin cocoons within wax hives (the cocoons are reused to store pollen and honey), and weaver ants use their larvae as ‘tools’ to fasten fresh plant leaves together to form large communal nests. (source)
But there is another silk producer you may not have heard of - the best insect OF ALL TIME! The Embioptera, fondly known as the webspinner. The webspinner produces about 150 strands of silk from each leg. He lays on his back on a tree trunk, and scrubs his little hands (I know insects don't have hands but watch the video below and you'll see what I'm saying!) back and forth, emitting silk above him. Essentially he lives under a sheet of silk so strong, insects walking on top of it cannot smell the webspinner just below and so waterproof that he must poke a hole in his silk sheet to get a drink of water. David Attenborough tells it much better than I do of course: