Spiders are co-doms with an apparently lethal super form (no super-spider has ever been proven--if they hatch at all, which is highly doubtful, they don't live long enough to breed, and they look exactly like spiders. It's more likely that they die in the egg before hatching).

Because of this, spiders are one of the most out-crossed morphs there is. People rarely breed two spiders together--there's no point in doing so, and it may lose you 25% of your clutch. This is how we know that the wobble cannot be bred out. It is probably a side-effect of the mutation that causes the spider pattern. We can surmise that some animals are more severely affected than others for a variety of reasons--some individuals show no outward signs of it, while, rarely, some are 'trainwrecks' so severely affected that they cannot function. Most are somewhere in between--showing minor ataxia signs, sometimes constantly, sometimes only when young or older, or during stressful times.

There are some people who believe that breeding 'non-wobble' spiders together will decrease the chance of wobble in the offspring, but I know of no records with sufficient numbers to support this theory. If someone has such records, they aren't sharing them. Most breeders at this point believe that all spiders carry the trait, and it's merely expressed more in some than others, and the expression is random -- spiders that don't wobble frequently have offspring that do wobble, and vice versa.

I think the bias some folks have against spiders that show the wobble trait is due to a desire to believe that what is clearly a neurological defect can't possibly be something that can't be eliminated from one of our favorite morphs...but really, at some point, the facts will have to be faced. Until proven otherwise, I side with the camp that believes the trait is part of the spider mutation itself, and cannot be eliminated. It rarely does harm in any case.