take soy, as an example.
some 80%+ of all soy is pressed for oil, but a soybean is only about 20% oil anyway. that leaves 80% of 80% of the total crop as industrial waste. we feed that to livestock. (we call it soymeal or soycake). so no insects are harmed to produce that for livestock: they were harmed to make soybean oil. by feeding the byproduct to livestock, we are conserving resources.
even the corn plant is a great example. people don’t eat corn leaves, cobs, or stalks, but livestock eat silage made from them.