I am sure your cats never achieve that 
True but cats have a far more developed brain than spiders....

Tel informs me that the conkers need to be cut in half as the spiders do not like the smell.
This of course means that spiders must have noses 
Several prolly.....
You are actually closer there than you might think BM, because a spider's cardio respiratory system is incredibly basic (which also limits its maximum size) it uses small pits in the lower leg called tarsal organs to detect smells. They do prefer some smells to others, for exampe the Kenyan Vampire Spider is attracted to the smell of unwashed feet and dirty socks but as far as repelling them try essential oils such as teatree or citrus as they could be overpowering to the receptors.