Could you get any nutritional value out of eating spider webs, if you needed food. Only the web is being asked about no detritus stuck to it.
Nutritional value or not, it would take thousands of spiders working full time to produce any significant amount of web filament to be useful.
Most likely more silk filaments. You could try eating a silk scarf to see how it tastes.
But that doesn’t mean it’s digestible, does it? I don’t think we can digest, uh, silkworm silk.
Even if you could digest it, there is so little stuff there that I doubt you would be able to extract anything of consequence. Unless you can gather a significant amount of webs, but I’m not sure how feasible it would be to gather even an ounce of the stuff.
Digestive proteases will likely chop spider silk up into absorbable pieces, but like pork rinds, silk has a very high glycine conten (table II).
Consequently, you’ll not get much nutritional goodness out of silk.
I was thinking more of in the case of starvation and the choice is spiderweb or nothing will it provide any benefit for keeping you alive. Think of an old cave or building festooned with spiderwebs if you must as I’m not concerned about how hard it is to gather. I know it’s a protein, but I didn’t think that necessarily made it something we could digest. Understanding the chemistry behind the digestion is beyond what I can think through any longer. Does anybody have anything to add to Squink’s statement?
Seems like you’d get better nutritional value mooching off the spider’s hard work and eating whatever the web catches rather than eat the web itself.
You know the silk has to be only a small percentage of a spider’s caloric value, since most spiders build and destroy their web frequently. The spiders themselves can digest the web, so they recycle those calories mostly. You can find an abstract here http://www.springerlink.com/content/p542477132g603v7/ that says:
Since 1 kcal (a dietary calorie) is 4184 J, you’d have to eat more than 3600 of that spider’s webs to get even a single calorie out of it. (Note that the 17435 J/g result is equivalent to pure protein/sugar, which is 4 calories to the gram). The spider itself, at 4 grams, would yield less than 20 calories.
Or just eat the spider…
This explains why my cat loves to eat them (usually with spider included).
It’s threads like these that keep me here. Not only that the question gets answered, but that it gets asked in the first place.
Thanks Annie-Xma. You have put a whole new perspective on D. A. thread such as this one! 
Thanks dracoi for some hard data on the subject.
Wouldn’t a 4 gm spider be a bit large on average? :dubious:
Thanks for participating so far. I’m still interested in more information if you have it.
Nah, the real treat is the spider. The web is just floss.
4 g is what the abstract mentioned for the spider that produced the webs they were studying. It is probably on the larger size, but garden spiders and orb spiders both get pretty substantial.
I’ll never forget mistaking a large garden spider for an acorn when I was a kid. I’m not particularly afraid of spiders, but I sure don’t expect acorns to suddenly unfold their legs when I pick them up!
Very old thread, but download this PDF if interested :
There’s at least 1 table showing the composition of various kinds of spider silk. But it always comes down to the fact it’s protein, and only the amino acid profile changes from one type of silk to the next, with glycine seeming to predominate.
So yeah, at 4 cal/g, and given the fact the silk is practically massless, even silk with the ideal amino acid profile for humans would contain virtually no nutritional value, and eating the spider itself (or other bugs) would make a lot more sense, if it came down to that.
Spiders not only eat their own webs, but also stuff that sticks to it. Not just insects, but also stuff like pollen. The pollen wouldn’t do much for humans, but is a significant source (about 25%) of nutrition for spiders.
Ripping off “The Far Side”:
Cat slurping up spider web: “Mmm, I just looove the crispy crunchy bits!”
The dust that settled on those cobwebs probably has more nutritional value.