In my world , there are a race of microscopic people ( 200 μm ) living in the stone age. They discover the spider mite , and promptly domesticate it for its silk . My question is -
How mite this race of microscopic people benefit from domesticating an organism that give them constant and easy access to spider silk?
( pun intended )
Spiders silk would probably not work as a luxury cloth in the same way we use it as a cloth, as at that scale it could be quite rough and simple, but on the other hand it would be an invaluable practical addition to their tribe / civilisation.
If you did weave it into a cloth, it could make for very good house insulation, or the skin of a tent, for it's heat regulating qualities, but I think the main benefit would be it's use as an extremely durable rope or cable (A major benefit to any civilisation). Perhaps useful enough for the people / tribe who can make the silk to become very prosperous through trading.
Also: the Physical Properties section on the Wikipedia article on silk makes for some good reading. Though it mainly refers to silk from the silkworm, it includes the diameter for spider (Argiope aurentia) silk at the bottom (3.57 μm). Not sure how relevant that is, because that spider looks much bigger than a silk mite, but it might help give a sense of scale, perhaps allowing you guess the diameter of a silk mites silk.
I don't know the properties of spider mite silk. The answer so far is that it is spider silk. I would find that out first. Spiders spin at least two kinds of silk. One is sticky and one isn't. A spider must walk on the non-sticky strands to keep from getting caught in its own web. But a mite doesn't spin webs to catch food, it does so to secure its eggs. Maybe it's all sticky, which could make it hard to use. I would also figure out what diameter the web is relative to the people. At the scale you have given, I kind of think it would be more like a rope than a thread, but maybe it could be reduced in size. Sorry I didn't look up all of that stuff, but just thought you might want to check on it for some realism.
As far as uses, in addition to the uses for the silk as others have mentioned, the micropeople might eat the eggs of the mite. They might figure out how to use the poop. Don't ask me what they would do with that, though. They might use the silk as a sort of glue. They might collect water in the form of dew off of the webs, although they could probably just do that on the leaves. Mites break through the cells of the plants. This might make it easier for them to use or eat whatever is in the plant cell.
Hope this helps.
If your silk is larger, it will have more industrious uses. Especially if it is large. Things like rope, tents, and other situations in which animal hides or leather would be used. Maybe they'd make saddles or boats out of it.
If it is smaller, and smoother, it might have uses such as clothing, or bedding. It would be like thread, although probably thick thread.
The eggs could be eaten, and that would work as well. These creatures might also be eaten, or something similar. They could be grown for their hard hides, which ae like stone and can be used to make tools. Don't be afraid to implant other uses in your mites, to make them more beneficial.
At that scale the silk would be incredibly strong. Even a single strand of it would be almost unbreakable to the micropeople. This suggests obvious uses as rope and in constructing shelters. At that size even a single drop of rain is a huge deal and surface tension starts ruling the behavior of water so something that's light enough for them to work with but able to protect them from rain would be a big deal.
Beyond that domesticating the mites would allow them to start on the agricultural and maybe even industrial revolution as they started using things other than their own muscles for power.
