The premise: A GM is starting up a new game, and wants to have a world with no spiders.
Result: people make suggestions. My personal favorite is the one where Lolth the Demon Queen of Spiders has been killed, and her death took all her little eight-legged minions out with her.
The results, it appears, might be pretty catastrophic.
Spiders: We’d Probably All Be Dead Without Them
Why? Because spiders are the dominant terrestrial predators on the planet.
Why? Because there are so many of them. (An acre of English meadow in late summer has been estimated to contain more than 2 million spiders, and it’s safe to assume that wetlands and undisturbed forest contain significantly more.)
Why else? They eat a lot. So what? Because they structure insect communities wherever they occur, spiders play a vital role in the terrestrial food chain. Without all those hungry, carnivorous spiders, insect populations would explode, food crops would be decimated, ecological balances would be ravaged, and humans would probably starve within a matter of months.”
http://nsdl.org/resource/2200/20061002152749782T
* Spiders are the largest entirely carnivorous order of animals.
* Assuming an average consumption of 0.1 gram of prey per spider per day, the spiders in one hectare of forest would consume 47,500 kilograms of prey per year–which is equal to 47.5 metric tons of insects!
Their sheer number make spiders vital in maintaining the balance of nature. Because they structure insect communities wherever they occur, spiders play a vital role in the terrestrial food chain. Without all those hungry spiders, insect populations would explode, food crops would be decimated, and ecological balances ravaged. Humans would probably starve within a matter of months–if they hadn’t already succumbed to various insect-borne diseases. No spider, incidentally, has been found to transmit disease.”
http://www.amnh.org/sciencebulletins/biobulletin/biobulletin/story1073.html
The spider is really man’s best friend. Imagine a world over-run with flies. Life would be intolerable! Without our friend the spider eating other insects like the fly, many serious pests would rise in number and present humankind with an incredible problem – one which would seriously affect our chances of survival. Even the good old household spider, like the little one I have here, does his part. Imagine how much it would cost to develop tiny little robots to roam over your house and clean up the maggots, eggs, flies, larva and other living things hidden away in every crack and cranny throughout your home. The spider does it all for you, and all for nothing. Most times he even has the sense to stay out of the way when you are around. So if you want to keep the real pests down, tolerate the spider a bit more in your home. If you really cannot bear to have one in the room with you, go and fetch a glass, pop it over the spider before he runs for it, and slip a postcard or stiff bit of paper under the glass to temporarily seal it in. You can then turn the glass upright and with the card or paper still held on top, take it out into the garden and let it go. One deft flick of the glass low to the ground should do it.”
http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/articles/nitemr3.html
Ecological impact of spider predation: a critical assessment of Bristowe’s and Turnbull’s estimates.
In any case, a fun little mind-game.