I'd leave a few to take care of some annoying insects. Daddy long-legs are good at that :P
No they fucking aren't. The last place I lived had those things crawling all over the place and there were still plenty of annoying little flying bugs buzzing around and annoying me. Spiders that are not doing their jobs properly are to be killed immediately.
Quote from BioSpark:
and afaik cannibalism is naturally occurring with a lot of insects.
I dont really know about 'conscience', but I think it's a safe assumption that they have no real thought. If they did, then at least ONE of them out of the untold numbers of them over time would have done something to indicate so.
about spiders and consciences though ... for one, they know what's right to eat and what's not right to eat. we call that instinct but to them it seems eating is the only thing that matters. so "right to eat" and "wrong to eat" is a huge factor.
i saw a movie in 8th grade about the oregon trail or something and the people traveling ran out of food and had to eat a family member who died to survive. fucked me up.