What is omitted before 'Similarly with animals'?

Question

I wasn't able to find the similar idioms in the dictionaries. What is omitted before 'Similarly with animals'?

Of cultivated crops, cereals were of the greatest economic importance in the Mediterranean region in ancient times, just as rice was the basic type of food in East Asia, and Indian maize and quinoa in the Americas. Since wild plants were necessarily self-seeding for their survival, the early Neolithic farmers favored individual plants that had developed suicidal mutations that prevented the pod from opening naturally and scattering the seed. Thus they were able to harvest their crops without losing grains, and could later separate the seeds from the pods. Similarly with animals: those that exhibited juvenile characteristics were favored over the strong, and bred to eliminate their wild characteristics. This ━ the earliest form of genetic manipulation by humans ━ was eventually to make a significant portion of Mediterranean flora and fauna dependent on human assistance in reproduction and survival: at least as sobering an innovation as the genetic modification of foods that is being debated at the beginning of the twenty-first century.

Ancient Technology By John William Humphrey

Answer 1

Nothing is omitted. There is a an adverb and an prepositional phrase that serve as an introduction to the sentence. You can argue that a colon should not have been used. Perhaps a comma would have been sufficient.

It just means the fact described in the sentence about animals is similar to that described in the previous sentence about plants. "With animals" means "in the case of animals"