The greater the diversity of food resources, the greater the species present, the happier the plants can be. Thus worms probably require some sort of balanced diet, just as people require a balanced diet. But what a balanced microbial diet is for a worm, we do not know with any great precision. There's more to learn. The Vermicompost Cycle Vermicompost is always bacterial-dominated when the worms are actually working on the food materials.
Worms tend to occupy the area just below the most recent additions of food waste material.
Probably the food waste needs to be colonized by bacteria and fungi before the worms will be interested in it, but fresh food waste material arrives with it's own set of bacteria and fungi already growing on it. Within one to two hours, in a healthy worm bin with a normal set of critters in it, worm bin bacteria and fungi have been inoculated on the fresh material, and in four to five hours, all open surfaces have an impressive layer of bacteria and fungi fully covering them. As these bacteria and fungi make waste products, other bacteria and fungi that were inoculated at the same time as the fresh surface-using bacteria and fungi wake up and start converting those waste products into other kinds of foods. Now protozoa, nematodes, microarthropods and of course, worms, are attracted to the new material. The worms grab the food pieces and drag them around, along with the associated bacteria, fungi, protozoa, and nematodes, inoculating anything nearby.