Foreshadowing and Fear

[Keeper of Dol Guldur]

I was just thinking, that for such an arachnophobiac (like myself) Tolkien didn't do a lot of foreshadowing for Shelob. While Gollum's oft-mentioned monologue referring to 'Her' helping him is certainly saying there is something nasty coming, it doesn't really convey any sort of knowledge of the fact that she is a spider-queen. We only really find out that she is a spider when Frodo and Sam run into silvery barriers, and come to the realization that they are webs. There aren't any small spiders which Sam swats away and mentions how nasty they look, or anything like that. You would think that Tolkien would give a little more warning to potential scaredy-cats (unless the point was to make somebody jump, as opposed to merely being creeped out). I just thought that was a little strange, given that other things were often alluded to frequently before they were unveiled.