I've had my male spider for 3+ years and he's never wobbled, spun, danced a jig or anything. He's produced two clutches, and a few babies have had a slight wobble during feeding time, but I've never seen it in him. The one male I have left from his clutch this year has never exhibited it either. So unless it's something that is going to show up later on down the road, I'd have to say you're wrong...unless you're "varying degree" includes none...