Silkworms are the oldest species cultivated by man. The varieties listed are all the same species. It is also about the only species of animal that does not exist in the wild only in cultivation. The zebra silkworms are sexually dimorphic. The males stay white. The females get zebra striped. This makes it easy to sex the worms and to choose breeding stock, such as picking the largest worms of either sex to allow to pupate for breeding stock as moths. Otherwise as far as health and other issues such as color of silk the zebras tend to be hardier and the colored silk means nothing once the moths come out because silk can only be used as silk by not allowing the moths to chew out. Nutrionally no difference.