A good test would be to compare the rates of spinning in spiders vs. their non spider siblings (and similarly the rates of kinking in caramels vs. their het and possible het siblings in breedings without homozygous caramels on both sides). A clutch of eggs is generally incubated together and they probably can’t identify the morph eggs from the non morph eggs early on so there should be no incubation bias between the eggs containing spiders and caramels and their normal looking siblings. Also, the genetics of the clutches should be the same except for the chromosome containing the respective morph.

If there is a statistically significant higher rate of spinning in the spiders than their non spider siblings or kinking in the caramels than their non caramel siblings then it almost has to be something genetic and if not the actual mutant gene its self at least a gene linked by being on the same chromosome. There have been loads of clutches producing spiders and non spider siblings produced and a fair number for caramels the public just doesn’t have the results.

The question then is why aren’t all spiders spinners or all caramels kinked. This is where there may be environmental or even genetic factors that mitigate the apparent genetic tendency toward these problems.