I'm going to go with the "do what makes YOU happy, and not worry about others" theory. I'm sure there are girls out there that won't like my tattoos, while there are some girls I know who actually like my tattoos.
In short, even if you don't get the tattoo, someone who is grossed out by spiders/scorpions has a good chance of not being compatable with you since you like them.
Besides. It's still got the same feel as skin. Paint yourself whatever skin colour you are when you 2 go out?